ALBERT

Description:    Micro-arthropods in moss patches have been used as a model system to investigate the effects of habitat destruction and fragmentation on population viability and ecosystem functioning. Previous assessments of the sensitivity to fragmentation and the effectiveness of mitigating landscape structures have to some extent been contradictory, one possible reason being a lack of knowledge of the realised dispersal distances of the species involved. We investigated the dispersal capabilities of oribatid mites (Acari: Oribatida) and springtails (Collembola) in an experimentally fragmented system consisting of bryophytes on a bare rock surface. We used defaunated patches that were recolonized from populated patches nearby as well as from a mainland surrounding the experimental arena, during 10 weeks in summer. We measured within-mainland, mainland-to-island, and island-to-island dispersal, and found that: (1) Oribatid mites were severely dispersal limited within the time frame of the experiment, even at isolation distances of only 5 cm; (2) springtails did not show any dispersal limitation over distances as far as 300 cm; (3) despite the observed dispersal limitation, the mainland had a relatively large influence on microarthropod occurrence, even at 300 cm distance; and (4) the dispersal rates were high enough for both species sorting and—in the case of collembolans—mass effects processes to occur. Our results indicate that fragmentation can strongly influence species occurrence and abundance in natural systems that are limited by dispersal. They also show that the presence of a distant mainland can override the influence of nearby habitat patches on local diversity and abundance. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2024-y Authors Jens Åström, Department of Ecology, SLU, Box 7044, 75007 Uppsala, Sweden Jan Bengtsson, Department of Ecology, SLU, Box 7044, 75007 Uppsala, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plant–soil interactions have been proposed as a causative mechanism explaining how invasive plant species impact ecosystem processes. We evaluate whether an invasive plant influences plant and soil-microbe acquisition of nitrogen to elucidate the mechanistic pathways by which invaders might alter N availability. Using a 15 N tracer, we quantify differences in nitrogen uptake and allocation in communities with and without Microstegium vimineum , a shade-tolerant, C 4 grass that is rapidly invading the understories of eastern US deciduous forests. We further investigate if plants or the microbial biomass exhibit preferences for certain nitrogen forms (glycine, nitrate, and ammonium) to gain insight into nitrogen partitioning in invaded communities. Understory native plants and M. vimineum took up similar amounts of added nitrogen but allocated it differently, with native plants allocating primarily to roots and M. vimineum allocating most nitrogen to shoots. Plant nitrogen uptake was higher in invaded communities due primarily to the increase in understory biomass when M. vimineum was present, but for the microbial biomass, nitrogen uptake did not vary with invasion status. This translated to a significant reduction ( P  〈 0.001) in the ratio of microbial biomass to plant biomass nitrogen uptake, which suggests that, although the demand for nitrogen has intensified, microbes continue to be effective nitrogen competitors. The microbial biomass exhibited a strong preference for ammonium over glycine and nitrate, regardless of invasion status. By comparison, native plants showed no nitrogen preferences and M. vimineum preferred inorganic nitrogen species. We interpret our findings as evidence that invasion by M. vimineum leads to changes in the partitioning of nitrogen above and belowground in forest understories, and to decreases in the microbial biomass, but it does not affect the outcome of plant–microbe–nitrogen interactions, possibly due to functional shifts in the microbial community as a result of invasion. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2030-0 Authors Jennifer M. Fraterrigo, Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801, USA Michael S. Strickland, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA Ashley D. Keiser, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA Mark A. Bradford, School of Forestry and Environmental Studies, Yale University, New Haven, CT 06511, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    We treated Norway spruce ( Picea abies ) stems with methyl jasmonate (MeJA) to determine possible quantitative and qualitative effects of induced tree defenses on pheromone emission by the spruce bark beetle Ips typographus . We measured the amounts of 2-methyl-3-buten-2-ol and (S)- cis -verbenol, the two main components of the beetle’s aggregation pheromone, released from beetle entrance holes, along with phloem terpene content and beetle performance in MeJA-treated and untreated Norway spruce logs. As expected, phloem terpene levels were higher and beetle tunnel length was shorter (an indication of poor performance) in MeJA-treated logs relative to untreated logs. Parallel to the higher phloem terpene content and poorer beetle performance, beetles in MeJA-treated logs released significantly less 2-methyl-3-buten-2-ol and (S)- cis -verbenol, and the ratio between the two pheromone components was significantly altered. These results suggest that host resistance elicited by MeJA application reduces pheromone emission by I. typographus and alters the critical ratio between the two main pheromone components needed to elicit aggregation. The results also provide a mechanistic explanation for the reduced performance and attractivity observed in earlier studies when bark beetles colonize trees with elicited host defenses, and extend our understanding of the ecological functions of conifer resistance against bark beetles. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2017-x Authors Tao Zhao, Department of Chemistry, Ecological Chemistry Group, Royal Institute of Technology, 100 44 Stockholm, Sweden Anna-Karin Borg-Karlson, Department of Chemistry, Ecological Chemistry Group, Royal Institute of Technology, 100 44 Stockholm, Sweden Nadir Erbilgin, Department of Renewable Resources, University of Alberta, 4-42 Earth Sciences Building Edmonton, Alberta, T6G 2E3 Canada Paal Krokene, Norwegian Forest and Landscape Institute, Raveien 9, 1431 Ås, Norway Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A positive effect of (meta)population density on emigration has been predicted by many theoretical models and confirmed empirically in various organisms. However, in butterflies, the most popular species for dispersal studies, the evidence for its existence has so far been equivocal, with negative relationships between density and emigration being reported more frequently. We analysed dispersal in sympatric metapopulations of two Maculinea butterflies, intensively surveyed with mark–release–recapture methods for 7 years. Dispersal parameters, derived using the virtual migration model, were assessed against butterfly densities, which fluctuated strongly over the study period. Emigration was positively correlated with density, and this effect was particularly strong at densities above carrying capacity, when emigration increased up to threefold in females and twofold in males compared with the normal levels. In turn, density had little impact on other dispersal parameters analysed. Our findings provide good evidence for positive density-dependence of emigration in butterflies. Emigrating at high densities is particularly beneficial for females, because it gives them a chance to lay part of their egg-load in less crowded patches, where offspring survival is higher due to lower intraspecific competition. Even though the rise in emigration becomes considerable at densities exceeding carrying capacity, i.e. relatively infrequently, it still has serious implications for many ecological phenomena, such as species range expansions, gene flow, and metapopulation persistence. Consequently, instead of treating emigration as a fixed trait, it is worth allowing for its density-dependence in applications such as population viability analyses, genetic models or metapopulation models. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2025-x Authors Piotr Nowicki, Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30–387 Kraków, Poland Vladimir Vrabec, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, Kamycka 129, Suchdol, 165 21 Prague 6, Czech Republic Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Motivated by persistent predictions of warming and drying in the entire Mediterranean and other regions, we have examined the interactions of intrinsic water-use efficiency ( W i ) with environmental conditions in Pinus halepensis . We used 30-year (1974–2003) tree-ring records of basal area increment (BAI) and cellulose 13 C and 18 O composition, complemented by short-term physiological measurements, from three sites across a precipitation ( P ) gradient (280–700 mm) in Israel. The results show a clear trend of increasing W i in both the earlywood (EW) and latewood (LW) that varied in magnitude depending on site and season, with the increase ranging from ca. 5 to 20% over the study period. These W i trends were better correlated with the increase in atmospheric CO 2 concentration, C a , than with the local increase in temperature (~0.04°C year −1 ), whereas age, height and density variations had minor effects on the long-term isotope record. There were no trends in P over time, but W i from EW and BAI were dependent on the interannual variations in P . From reconstructed C i values, we demonstrate that contrasting gas-exchange responses at opposing ends of the hydrologic gradient underlie the variation in W i sensitivity to C a between sites and seasons. Under the mild water limitations typical of the main seasonal growth period, regulation was directed at increasing C i / C a towards a homeostatic set-point observed at the most mesic site, with a decrease in the W i response to C i with increasing aridity. With more extreme drought stress, as seen in the late season at the drier sites, the response was W i driven, and there was an increase in the W i sensitivity to C a with aridity and a decreasing sensitivity of C i to C a . The apparent C a -driven increases in W i can help to identify the adjustments to drying conditions that forest ecosystems can make in the face of predicted atmospheric change. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2010-4 Authors Kadmiel Maseyk, Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, 76100 Rehovot, Israel Debbie Hemming, Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, 76100 Rehovot, Israel Alon Angert, Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, 76100 Rehovot, Israel Steven W. Leavitt, Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 85721, USA Dan Yakir, Department of Environmental Sciences and Energy Research, Weizmann Institute of Science, 76100 Rehovot, Israel Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The impact of parasites on population dynamics is well documented, but less is known on how host population density affects parasite spread. This relationship is difficult to assess because of confounding effects of social structure, population density, and environmental conditions that lead to biased among-population comparisons. Here, we analyzed the infestation by two groups of nematodes (gastro-intestinal (GI) strongyles and Trichuris ) in the roe deer ( Capreolus capreolus ) population of Trois Fontaines (France) between 1997 and 2007. During this period, we experimentally manipulated population density through changes in removals. Using measures collected on 297 individuals, we quantified the impact of density on parasite spread after taking into account possible influences of date, age, sex, body mass, and weather conditions. The prevalence and abundance of eggs of both parasites in females were positively related to roe deer density, except Trichuris in adult females. We also found a negative relationship between parasitism and body mass, and strong age and sex-dependent patterns of parasitism. Prime-age adults were less often parasitized and had lower fecal egg counts than fawns or old individuals, and males were more heavily and more often infected than females. Trichuris parasites were not affected by weather, whereas GI strongyles were less present after dry and hot summers. In the range of observed densities, the observed effect of density likely involves a variation of the exposure rate, as opposed to variation in host susceptibility. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2018-9 Authors Guillaume Body, Université de Lyon, Université Lyon 1, UMR5558 Laboratoire de Biométrie et Biologie Evolutive, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France Hubert Ferté, JE 2533-USC ANSES « VECPAR » UFR de Pharmacie, Université de Reims Champagne-Ardenne, 51 rue Cognacq-Jay, 51096 Reims, France Jean-Michel Gaillard, Université de Lyon, Université Lyon 1, UMR5558 Laboratoire de Biométrie et Biologie Evolutive, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France Daniel Delorme, Centre National d’Etude et de Recherche Appliquées sur les Cervidés-Sangliers, Office National de la Chasse et de la Faune Sauvage, 1 Place Exelmans, 55000 Bar-le-Duc, France François Klein, Centre National d’Etude et de Recherche Appliquées sur les Cervidés-Sangliers, Office National de la Chasse et de la Faune Sauvage, 1 Place Exelmans, 55000 Bar-le-Duc, France Emmanuelle Gilot-Fromont, Université de Lyon, Université Lyon 1, UMR5558 Laboratoire de Biométrie et Biologie Evolutive, 43 Bd du 11 novembre 1918, 69622 Villeurbanne Cedex, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Mature forest canopies sustain an enormous diversity of herbivorous arthropods; however, with the exception of species that exhibit large-scale outbreaks, canopy arthropods are thought to have relatively little influence on overall forest productivity. Diminutive gall-inducing mites (Acari; Eriophyoidae) are ubiquitous in forest canopies and are almost always highly host specific, but despite their pervasive occurrence, the impacts of these obligate parasites on canopy physiology have not been examined. We have documented large declines in photosynthetic capacity (approx. 60%) and stomatal conductance (approx. 50%) in canopy leaves of mature sugar maple ( Acer saccharum ) trees frequently galled by the maple spindle gall mite Vasates aceriscrumena . Remarkably, such large impacts occurred at very low levels of galling, with the presence of only a few galls (occupying approx. 1% of leaf area) compromising gas-exchange across the entire leaf. In contrast to these extreme impacts on the leaves of adult trees, galls had no detectible effect on the gas-exchange of maple saplings, implying large ontogenetic differences in host tolerance to mite galling. We also found a significant negative correlation between canopy tree radial increment growth and levels of mite galling. Increased galling levels and higher physiological susceptibility in older canopy trees thus suggest that gall-inducing mites may be major drivers of “age-dependent” reductions in the physiological performance and growth of older trees. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2019-8 Authors Rajit Patankar, Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S 3B2 Sean C. Thomas, Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S 3B2 Sandy M. Smith, Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, Canada M5S 3B2 Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Infection-induced changes in a host’s thermal physiology can represent (1) a generalized host response to infection, (2) a pathological side-effect of infection, or (3), provided the parasite’s development is temperature-dependent, a subtle case of host manipulation. This study investigates parasite-induced changes in the thermal biology of a first intermediate host infected by two castrating trematodes (genera Maritrema and Philophthalmus ) using laboratory experiments and field surveys. The heat tolerance and temperatures selected by the snail, Zeacumantus subcarinatus , displayed alterations upon infection that differed between the two trematodes. Upon heating, snails infected by Maritrema sustained activity for longer durations than uninfected snails, followed by a more rapid recovery, and selected higher temperatures in a thermal gradient. These snails were also relatively abundant in high shore localities in the summer only, corresponding with seasonal elevated microhabitat temperatures. By contrast, Philophthalmus -infected snails fell rapidly into a coma upon heating and did not display altered thermal preferences. The respective heat tolerance of each trematode corresponded with the thermal responses induced in the snail: Maritrema survived exposure to 40°C, while Philophthalmus was less heat tolerant. Although both trematodes infect the same tissues, Philophthalmus leads to a reduction in the host’s thermal tolerance, a response consistent with a pathological side effect. By contrast, Maritrema induces heat tolerance in the snail and withstood exposure to high heat. As the developmental rate and infectivity of Maritrema increase with temperature up to 25°C, one adaptive explanation for our findings is that Maritrema manipulates the snail’s thermal responses to exploit warm microhabitats. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2014-0 Authors A. E. Bates, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand F. Leiterer, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand M. L. Wiedeback, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand R. Poulin, Zoology Department, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A cost of reproduction in terms of reduced future performance underlies all life-history models, yet costs have been difficult to detect in short-term experiments with long-lived plants. The likelihood of detecting costs should depend on the range of variation in reproductive effort that can be induced, and also on the shape of the cost function across this range, which should be affected by resource availability. Here, we experimentally examined the effects of both reduced and increased fruit production in two populations of the long-lived orchid Gymnadenia conopsea located at sites that differ in length of the growing season. Plants that were prevented from fruiting produced more flowers in the population with a longer growing season, had higher survival in the other population, and grew larger compared to control plants in both populations. Fruit production was pollen-limited in both populations, and increased reproductive investment after supplemental hand-pollination was associated with reduced fecundity the following year. The results demonstrate that the shape of the cost function varies among fitness components, and that costs can be differentially expressed in different populations. They are consistent with the hypothesis that differences in temporal overlap between allocation to reproduction and other functions will induce among-population variation in reproductive costs. Content Type Journal Article Pages 1-8 DOI 10.1007/s00442-011-2006-0 Authors Nina Sletvold, NTNU, Museum of Natural History and Archaeology, 7491 Trondheim, Norway Jon Ågren, Plant Ecology and Evolution, Department of Ecology and Genetics, EBC, Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Within-range effects of climatic change on tree growth at the sub-regional scale remain poorly understood. The aim of this research was to use climate and radial-growth data to explain how long-term climatic trends affect tree growth patterns along the southern limit of the range of Pinus nigra ssp. salzmannii (Eastern Baetic Range, southern Spain). We used regional temperature and precipitation data and measured sub-regional radial growth variation in P. nigra forests over the past two centuries. A dynamic factor analysis was applied to test the hypothesis that trees subjected to different climates have experienced contrasting long-term growth variability. We defined four representative stand types based on average temperature and precipitation to evaluate climate–growth relationships using linear mixed-effect models and multi-model selection criteria. All four stand types experienced warming and declining precipitation throughout the twentieth century. From the onset of the twentieth century, synchronised basal-area increment decline was accounted for by dynamic factor analysis and was related to drought by climate–growth models; declining basal-area increment trends proved stronger at lower elevations, whereas temperature was positively related to growth in areas with high rainfall inputs. Given the contrasting sub-regional tree-growth responses to climate change, the role of drought becomes even more complex in shaping communities and affecting selection pressure in the Mediterranean mountain forests. Potential vegetation shifts will likely occur over the dry edge of species distributions, with major impacts on ecosystem structure and function. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2012-2 Authors Juan Carlos Linares, Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera km. 1, 41002 Sevilla, Spain Pedro Antonio Tíscar, Centro de Capacitación y Experimentación Forestal, 23470 Cazorla, Spain Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plants in nutrient-poor environments typically have low foliar nitrogen (N) concentrations, long-lived tissues with leaf traits designed to use nutrients efficiently, and low rates of photosynthesis. We postulated that increasing N availability due to atmospheric deposition would increase photosynthetic capacity, foliar N, and specific leaf area (SLA) of bog shrubs. We measured photosynthesis, foliar chemistry and leaf morphology in three ericaceous shrubs ( Vaccinium myrtilloides , Ledum groenlandicum and Chamaedaphne calyculata ) in a long-term fertilization experiment at Mer Bleue bog, Ontario, Canada, with a background deposition of 0.8 g N m −2  a −1 . While biomass and chlorophyll concentrations increased in the highest nutrient treatment for C. calyculata , we found no change in the rates of light-saturated photosynthesis ( A max ), carboxylation ( V cmax ) , or SLA with nutrient (N with and without PK) addition, with the exception of a weak positive correlation between foliar N and A max for C. calyculata , and higher V cmax in L. groenlandicum with low nutrient addition. We found negative correlations between photosynthetic N use efficiency (PNUE) and foliar N, accompanied by a species-specific increase in one or more amino acids, which may be a sign of excess N availability and/or a mechanism to reduce ammonium (NH 4 ) toxicity. We also observed a decrease in foliar soluble Ca and Mg concentrations, essential minerals for plant growth, but no change in polyamines, indicators of physiological stress under conditions of high N accumulation. These results suggest that plants adapted to low-nutrient environments do not shift their resource allocation to photosynthetic processes, even after reaching N sufficiency, but instead store the excess N in organic compounds for future use. In the long term, bog species may not be able to take advantage of elevated nutrients, resulting in them being replaced by species that are better adapted to a higher nutrient environment. Content Type Journal Article Pages 1-14 DOI 10.1007/s00442-011-1998-9 Authors Jill L. Bubier, Environmental Studies Program, Mount Holyoke College, 50 College Street, South Hadley, MA 01075, USA Rose Smith, Environmental Studies Program, Mount Holyoke College, 50 College Street, South Hadley, MA 01075, USA Sari Juutinen, Environmental Studies Program, Mount Holyoke College, 50 College Street, South Hadley, MA 01075, USA Tim R. Moore, Department of Geography, Global Environmental & Climate Change Centre, McGill University, 805 Sherbrooke St. W, Montreal, QC H3A 2K6, Canada Rakesh Minocha, US Department of Agriculture, Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA Stephanie Long, US Department of Agriculture, Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA Subhash Minocha, Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    There is considerable variation in cannibalism between different species and also between individuals of different species, although relatively little is known about what creates this variation. We investigated the degree of cannibalism in guppy ( Poecilia reticulata ) populations originating from high and low predation environments in Trinidad, and also how cannibalism was affected by the presence of refuges. Females from two populations were allowed to feed on juveniles from two populations in aquaria trials. The cannibalism was size-dependent and varied depending on both juvenile and female origin. Low predation females were more efficient cannibals and low predation juveniles were better at avoiding cannibalism compared to high predation guppies when no refuges were present. The high predation females were superior cannibals and the high predation juveniles were better at escaping cannibalism than the low predation guppies when refuges were present. We discuss whether the differences in cannibalism and response to refuge addition relate to predation-induced habitat shifts and differences in the guppies’ natural environment. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1990-4 Authors Karin A. Nilsson, Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden Sofi Lundbäck, Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden Alexandra Postavnicheva-Harri, Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden Lennart Persson, Department of Ecology and Environmental Science, Umeå University, 901 87 Umeå, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    During the first few years of elevated atmospheric [CO 2 ] treatment at the Nevada Desert FACE Facility, photosynthetic downregulation was observed in desert shrubs grown under elevated [CO 2 ], especially under relatively wet environmental conditions. Nonetheless, those plants maintained increased A sat (photosynthetic performance at saturating light and treatment [CO 2 ]) under wet conditions, but to a much lesser extent under dry conditions. To determine if plants continued to downregulate during long-term exposure to elevated [CO 2 ], responses of photosynthesis to elevated [CO 2 ] were examined in two dominant Mojave Desert shrubs, the evergreen Larrea tridentata and the drought-deciduous Ambrosia dumosa , during the eighth full growing season of elevated [CO 2 ] treatment at the NDFF. A comprehensive suite of physiological processes were collected. Furthermore, we used C labeling of air to assess carbon allocation and partitioning as measures of C sink activity. Results show that elevated [CO 2 ] enhanced photosynthetic performance and plant water status in Larrea , especially during periods of environmental stress, but not in Ambrosia . δ 13 C analyses indicate that Larrea under elevated [CO 2 ] allocated a greater proportion of newly assimilated C to C sinks than Ambrosia . Maintenance by Larrea of C sinks during the dry season partially explained the reduced [CO 2 ] effect on leaf carbohydrate content during summer, which in turn lessened carbohydrate build-up and feedback inhibition of photosynthesis. δ 13 C results also showed that in a year when plant growth reached the highest rates in 5 years, 4% ( Larrea ) and 7% ( Ambrosia ) of C in newly emerging organs were remobilized from C that was assimilated and stored for at least 2 years prior to the current study. Thus, after 8 years of continuous exposure to elevated [CO 2 ], both desert perennials maintained their photosynthetic capacities under elevated [CO 2 ]. We conclude that C storage, remobilization, and partitioning influence the responsiveness of these desert shrubs during long-term exposure to elevated [CO 2 ]. Content Type Journal Article Pages 1-16 DOI 10.1007/s00442-011-1996-y Authors Iker Aranjuelo, Fisiologia Vegetal y Agrobiologia, Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Campus de Arrosadia, 31192 Mutilva Baja, Spain Allison L. Ebbets, School of Life Sciences, University of Nevada, Las Vegas, NV 89154-4004, USA R. Dave Evans, School of Biological Sciences, Washington State University, Pullman Washington, 99164 USA David T. Tissue, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Salvador Nogués, Unitat de Fisologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain Natasja van Gestel, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Paxton Payton, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Volker Ebbert, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA Williams W. Adams III, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA Robert S. Nowak, Department of Natural Resources and Environmental Science, University of Nevada, Reno Nevada, 89557 USA Stanley D. Smith, School of Life Sciences, University of Nevada, Las Vegas, NV 89154-4004, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Generally in birds, the classic sex roles of male competition and female choice result in females providing most offspring care while males face uncertain parentage. In less than 5% of species, however, reversed courtship sex roles lead to predominantly male care and low extra-pair paternity. These role-reversed species usually have reversed sexual size dimorphism and polyandry, confirming that sexual selection acts most strongly on the sex with the smaller parental investment and accordingly higher potential reproductive rate. We used parentage analyses and observations from three field seasons to establish the social and genetic mating system of pheasant coucals, Centropus phasianinus , a tropical nesting cuckoo, where males are much smaller than females and provide most parental care. Pheasant coucals are socially monogamous and in this study males produced about 80% of calls in the dawn chorus, implying greater male sexual competition. Despite the substantial male investments, extra-pair paternity was unusually high for a socially monogamous, duetting species. Using two or more mismatches to determine extra-pair parentage, we found that 11 of 59 young (18.6%) in 10 of 21 broods (47.6%) were not sired by their putative father. Male incubation, starting early in the laying sequence, may give the female opportunity and reason to seek these extra-pair copulations. Monogamy, rather than the polyandry and sex-role reversal typical of its congener, C. grillii , may be the result of the large territory size, which could prevent females from monopolising multiple males. The pheasant coucal’s exceptional combination of classic sex-roles and male-biased care for extra-pair young is hard to reconcile with current sexual selection theory, but may represent an intermediate stage in the evolution of polyandry or an evolutionary remnant of polyandry. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2002-4 Authors G. Maurer, Centre for Ornithology, University of Birmingham, B15 2TT Birmingham, UK M. C. Double, Australian Antarctic Division, 203 Channel Highway, Kingston, TAS 7050, Australia O. Milenkaya, Department of Biological Sciences, Virginia Tech, 4107 Derring Hall, Blacksburg, VA 24061, USA M. Süsser, Naturschutzbund Deutschland, 10108 Berlin, Germany R. D. Magrath, Research School of Biology, The Australian National University Canberra, Canberra, ACT 0200, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The relationship between inorganic nitrogen (N) cycling and plant productivity is well established. However, recent research has demonstrated the ability of plants to take up low molecular weight organic N compounds (i.e., amino acids) at rates that often rival those of inorganic N forms. In this study, we hypothesize that temperate forest tree species characteristic of low-fertility habitats will prefer amino acids over species characteristic of high-fertility habitats. We measured the uptake of 15 N-labeled amino acids (glycine, glutamine, arginine, serine), ammonium (NH 4 + ), and nitrate (NO 3 − ) by four tree species that commonly occur in eastern North America, where their abundances have been correlated with inorganic N availability. Specific uptake rates of amino acids were largely similar for all tree species; however, high-fertility species took up NH 4 + at rates more than double those of low-fertility species, rendering amino acid N relatively more important to the N nutrition of low-fertility species. Low-fertility species acquired over four times more total N from arginine compared to NH 4 + and NO 3 − ; high-fertility species acquired the most N from NH 4 + . Arginine had the highest uptake rates of any amino acid by all species; there were no significant differences in uptake rates of the remaining amino acids. Our results support the idea that the dominant species in a particular habitat are those best able to utilize the most available N resources. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2009-x Authors Emily E. Scott, Department of Forestry, Michigan State University, East Lansing, MI 48824, USA David E. Rothstein, Department of Forestry, Michigan State University, East Lansing, MI 48824, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Conditions experienced in early life have been shown to affect the development or programming of physiological processes. While animals may recover from earlier periods of adversity, this process can carry long-term costs. Such long-term effects are likely to be most evident when individuals are placed in demanding situations that require high performance. Escape flight speed in passerine birds is crucial to predator evasion and requires very rapid take-off. Here, we examine whether the ability to maintain escape flight performance during the immediate post-breeding period is influenced by conditions in early life. We manipulated the early life conditions experienced by zebra finches ( Taeniopygia guttata ) by rearing them on either low or high quality food through the growth period, or by changing conditions halfway through the nestling period, moving from high to low or vice versa. While there was no difference amongst the treatment groups in body size attained by adulthood, amongst the birds that experienced low quality food, the body size of those that were switched to a high quality diet halfway through the nestling growth period recovered faster than those that had low quality food until fledging. We found no differences amongst the dietary groups in flight performance at adulthood prior to breeding, and all groups showed a decline in average escape flight performance over the breeding period. However, the magnitude of the post-breeding decline in flight performance for a given level of reproductive output was significantly greater for those females that had experienced a switch from a low to a high quality diet during the nestling phase. These results suggest that this diet-induced rapid recovery of body size, which may have immediate competitive advantages, nonetheless carries locomotory costs in later life manifest in the capacity to sustain the high performance escape response during the post-reproductive recovery phase. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1986-0 Authors François Criscuolo, IPHC, Département d’Ecologie, Physiologie et Ethologie, CNRS, University of Strasbourg, 23 rue Becquerel, 67087 Strasbourg Cedex 2, France Pat Monaghan, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK Audrey Proust, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK Jana Škorpilová, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK John Laurie, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK Neil B. Metcalfe, College of Medical, Veterinary and Life Sciences, University of Glasgow, Graham Kerr Building, Glasgow, G12 8QQ UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Because palms grow in highly varying climates and reach considerable heights, they present a unique opportunity to evaluate how environment and plant size impact hydraulic function. We studied hydraulic properties of petioles from palms of varying height from three species: Iriartea deltoidea , a tropical rainforest species; Mauritia flexuosa , a tropical rainforest, swamp species; and Washingtonia robusta , a subtropical species. We measured leaf areas, petiole cross-sectional areas, specific conductivity ( K S ), petiole anatomical properties, vulnerability to embolism and leaf water potentials and calculated petiole Huber values and leaf-specific conductivities ( K L ). Leaf and petiole cross-sectional areas varied widely with height. However, hydraulic properties including Huber values, K S and K L , remained constant. The two palmate species, M. flexuosa and W. robusta, had larger Huber values than I. deltoidea, a pinnately-compound species which exhibited the highest K S . Metaxylem vessel diameters and vascular bundle densities varied with height in opposing patterns to maintain petiole conductivities. I. deltoidea and W. robusta petioles had similar P 50 values (the point at which 50% of hydraulic conductivity is lost) averaged over all crown heights, but W. robusta exhibited more negative P 50 values in taller palms. Comparison of P 50 values with transpiring midday leaf water potentials, as well as a double-dye staining experiment in a 1-m-tall palm, suggested that a fairly significant amount of embolisms were occurring and refilled on a diurnal basis. Therefore, across palms differing widely in height and growing environments, we found convergence in water transport per unit leaf area ( K L ) with individuals exhibiting differing strategies for achieving this. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2038-5 Authors Heidi J. Renninger, Department of Geography and Environment, Boston University, 675 Commonwealth Ave, Boston, MA 02215, USA Nathan Phillips, Department of Geography and Environment, Boston University, 675 Commonwealth Ave, Boston, MA 02215, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    As the number and intensity of threats to biodiversity increase, there is a critical need to investigate interactions between threats and manage populations accordingly. We ask whether it is possible to reduce the effects of one threat by mitigating another. We used long-term data for the long-lived resprouter, Xanthorrhoea resinosa Pers., to parameterise an individual-based population model. This plant is currently threatened by adverse fire regimes and the pathogen Phytophthora cinnamomi . We tested a range of fire and disease scenarios over various time horizons relevant to the population dynamics of the species and the practicalities of management. While fire does not kill the disease, it does trigger plant demographic responses that may promote population persistence when disease is present. Population decline is reduced with frequent fires because they promote the greatest number of germination events, but frequent fires reduce adult stages, which is detrimental in the long term. Fire suppression is the best action for the non-seedling stages but does not promote recruitment. With disease, frequent fire produced the highest total population sizes for shorter durations, but for longer durations fire suppression gave the highest population sizes. When seedlings were excluded, fire suppression was the best action. We conclude that fire management can play an important role in mitigating threats posed by this disease. The best approach to reducing declines may be to manage populations across a spatial mosaic in which the sequence of frequent fires and suppression are staggered across patches depending on the level of disease at the site. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2029-6 Authors Helen M. Regan, Biology Department, University of California, 900 University Ave, Riverside, CA 92521, USA David A. Keith, NSW Office of Environment and Heritage, Hurstville, NSW 2220, Australia Tracey J. Regan, School of Botany, The University of Melbourne, Parkville, Victoria, 3010 Australia Mark G. Tozer, NSW Office of Environment and Heritage, Hurstville, NSW 2220, Australia Naomi Tootell, Department of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria 3010, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Strong interactions between dry-fruited shrubs and seed-harvesting ants are expected in early successional scrubs, where both groups have a major presence. We have analysed the implications of the seed characteristics of two dry-fruited shrub species ( Coronilla minima and Dorycnium pentaphyllum ) on seed predation and dispersal mediated by harvester ants and the consequences of these processes on spatio-temporal patterns of plant abundance in a heterogeneous environment. We found that large C. minima seeds were collected much more (39%) than small D. pentaphyllum seeds (2%). However, not all of the removed seeds of these plant species were consumed, and 12.8% of the seeds were lost along the trails, which increased dispersal distances compared with abiotic dispersal alone. Seed dropping occurred among all microhabitats of the two plant species, but especially in open microhabitats, which are the most suitable ones for plant establishment. The two plant species increased their presence in the study area during the study period: C. minima in open microhabitats and D. pentaphyllum in high vegetation. The large size of C. minima seeds probably limited the primary seed dispersal of this species, but may have allowed strong interaction with ants. Thus, seed dispersal by ants resulted in C. minima seeds reaching more suitable microhabitats by means of increasing dispersal distance and redistribution among microhabitats. In contrast, the smaller size of D. pentaphyllum seeds arguably allows abiotic seed dispersal over longer distances and colonization of all types of microhabitats, although it probably also limits their interaction with ants and, consequently, their redistribution in suitable microhabitats. We suggest that dyszoochory could contribute to the success of plant species with different seed characteristics in scrub habitats where seeds are abundantly collected by seed-harvesting ants. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2034-9 Authors Xavier Arnan, Unitat d’Ecologia i CREAF, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain A. Rodrigo, Unitat d’Ecologia i CREAF, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain J. Retana, Unitat d’Ecologia i CREAF, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Our experiments addressed systemic metabolic effects in above-ground plant tissue as part of the plant’s response to the arbuscular mycorrhizal (AM) interaction. Due to the physiology of this interaction, we expected effects in the areas of plant mineral nutrition, carbon allocation and stress-related metabolism, but also a notable dependence of respective metabolic changes on environmental conditions and on plant developmental programs. To assess these issues, we analyzed metabolite profiles from mycorrhizal and non-mycorrhizal Lotus japonicus grown under greenhouse conditions at three different time points in the growing season in three different above-ground organs (flowers, sink leaves and source leaves). Statistical analysis of our data revealed a number of significant changes in individual experiments with little overlap between these experiments, indicating the expected impact of external conditions on the plant’s response to AM colonization. Partial least square-discriminant analysis (PLS-DA) nevertheless revealed considerable similarities between the datasets, and loading analysis of the component separating mycorrhizal and non-mycorrhizal plants allowed the defining of a core set of metabolites responsible for this separation. This core set was observed in experiments with and without mycorrhiza-induced growth effects. It corroborated trends already indicated by the significant changes from individual experiments and suggested a negative systemic impact of AM colonization on central catabolic metabolism as well as on amino acid metabolism. In addition, metabolic signals for an increase in stress experienced by plant tissue were recorded in flowers and source leaves. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2037-6 Authors Thomas Fester, Helmholtz Centre for Environmental Research, UFZ, Permoserstraße 15, 04318 Leipzig, Germany Ingo Fetzer, Helmholtz Centre for Environmental Research, UFZ, Permoserstraße 15, 04318 Leipzig, Germany Sabine Buchert, Dahlem Center of Plant Sciences, Plant Ecology, Institute of Biology, Free University of Berlin, Altensteinstraße 6, 14195 Berlin, Germany Rico Lucas, Helmholtz Centre for Environmental Research, UFZ, Permoserstraße 15, 04318 Leipzig, Germany Matthias C. Rillig, Dahlem Center of Plant Sciences, Plant Ecology, Institute of Biology, Free University of Berlin, Altensteinstraße 6, 14195 Berlin, Germany Claus Härtig, Helmholtz Centre for Environmental Research, UFZ, Permoserstraße 15, 04318 Leipzig, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    We examined how the galling aphid Pemphigus batae manipulates resource translocation patterns of resistant and susceptible narrowleaf cottonwood Populus angustifolia . Using carbon-14 ( 14 C)-labeling experiments in common garden trials, five patterns emerged. First, although aphid galls on resistant and susceptible genotypes did not differ in their capacity to intercept assimilates exported from the leaf they occupied, aphids sequestered 5.8-fold more assimilates from surrounding leaves on susceptible tree genotypes compared to resistant genotypes. Second, gall sinks on the same side of a shoot as a labeled leaf were 3.4-fold stronger than gall sinks on the opposite side of a shoot, which agrees with patterns of vascular connections among leaves of the same shoot (orthostichy). Third, plant genetic-based traits accounted for 26% of the variation in sink strength of gall sinks and 41% of the variation in sink strength of a plant’s own bud sinks. Fourth, tree susceptibility to aphid gall formation accounted for 63% of the variation in 14 C import, suggesting strong genetic control of sink–source relationships. Fifth, competition between two galls was observed on a susceptible but not a resistant tree. On the susceptible tree distal aphids intercepted 1.5-fold more 14 C from the occupied leaf than did basal aphids, but basal aphids compensated for the presence of a distal competitor by almost doubling import to the gall from surrounding leaves. These findings and others, aimed at identifying candidate genes for resistance, argue the importance of including plant genetics in future studies of the manipulation of translocation patterns by phytophageous insects. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2033-x Authors Zacchaeus G. Compson, Cottonwood Ecology Group, Department of Biology, Northern Arizona University, Flagstaff, AZ 86011-5640, USA Katherine C. Larson, Department of Biology, University of Central Arkansas, Conway, AR 72035, USA Matthew S. Zinkgraf, Cottonwood Ecology Group, Department of Biology, Northern Arizona University, Flagstaff, AZ 86011-5640, USA Thomas G. Whitham, Cottonwood Ecology Group, Department of Biology, Northern Arizona University, Flagstaff, AZ 86011-5640, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Carbon, nitrogen, and phosphorus (C, N, P) stoichiometry influences the growth of plants and nutrient cycling within ecosystems. Indeed, elemental ratios are used as an index for functional differences between plants and their responses to natural or anthropogenic variations in nutrient supply. We investigated the variation in growth and elemental content of the rootless terrestrial bromeliad Tillandsia landbeckii , which obtains its moisture, and likely its nutrients, from coastal fogs in the Atacama Desert. We assessed (1) how fog nutrient supply influences plant growth and stoichiometry and (2) the response of plant growth and stoichiometry to variations in nutrient supply by using reciprocal transplants. We hypothesized that T. landbeckii should exhibit physiological and biochemical plastic responses commensurate with nutrient supply from atmospheric deposition. In the case of the Atacama Desert, nutrient supply from fog is variable over space and time, which suggests a relatively high variation in the growth and elemental content of atmospheric bromeliads. We found that the nutrient content of T. landbeckii showed high spatio-temporal variability, driven partially by fog nutrient deposition but also by plant growth rates. Reciprocal transplant experiments showed that transplanted individuals converged to similar nutrient content, growth rates, and leaf production of resident plants at each site, reflecting local nutrient availability. Although plant nutrient content did not exactly match the relative supply of N and P, our results suggest that atmospheric nutrient supply is a dominant driver of plant growth and stoichiometry. In fact, our results indicate that N uptake by T. landbeckii plants depends more on N supplied by fog, whereas P uptake is mainly regulated by within-plant nutrient demand for growth. Overall, these findings indicate that variation in fog nutrient supply exerts a strong control over growth and nutrient dynamics of atmospheric plants, which are ubiquitous across fog-dominated ecosystems. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2032-y Authors Angélica L. González, Departamento de Ecología, Center for Advanced Studies in Ecology and Biodiversity (CASEB), Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile José Miguel Fariña, Departamento de Ecología, Center for Advanced Studies in Ecology and Biodiversity (CASEB), Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile Raquel Pinto, Universidad Arturo Prat, Iquique, Chile Cecilia Pérez, Departamento de Ecología, Center for Advanced Studies in Ecology and Biodiversity (CASEB), Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile Kathleen C. Weathers, Cary Institute of Ecosystem Studies, Box AB, Millbrook, NY 12545, USA Juan J. Armesto, Departamento de Ecología, Center for Advanced Studies in Ecology and Biodiversity (CASEB), Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile Pablo A. Marquet, Departamento de Ecología, Center for Advanced Studies in Ecology and Biodiversity (CASEB), Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Carbon-based secondary metabolites (CBSMs) are assumed to function as defences that contribute to herbivore-avoidance strategies of woody plants. Severe browsing has been reported to reduce concentrations of CBSMs and increase N concentrations in individual plants, causing heavily browsed plants to be characterised by N-rich/C-poor tissues. We hypothesised that concentrations of condensed tannins (CT) and total polyphenols (TP) should decrease, or N increase, in relation to increasing intensity of browsing, rendering severely browsed plants potentially more palatable (increased N:CT) and less N-limited (increased N:P) than lightly browsed ones. We sampled naturally browsed trees (taller than 2 m) of four abundant species in southern Kruger National Park, South Africa. Species-specific relationships between N:CT, CT, TP and P concentrations and increasing browsing intensity were detected, but N and N:P were consistently invariable. We developed a conceptual post-hoc model to explain diverse species-specific CBSM responses on the basis of relative allocation of C to total C-based defence traits (e.g. spines/thorns, tough/evergreen leaves, phenolic compounds). The model suggests that species with low allocation of C to C-based defence traits become C-limited (potentially more palatable) at higher browsing intensity than species with high allocation of C to C-based defences. The model also suggests that when N availability is high, plants become C-limited at higher browsing intensity than when N availability is low. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2042-9 Authors Peter F. Scogings, Department of Agriculture, University of Zululand, Private Bag X1001, KwaDlangezwa, 3886 South Africa Joakim Hjältén, Department of Wildlife, Fish and Environmental Studies, Swedish University of Agricultural Sciences, Umeå, Sweden Christina Skarpe, Faculty of Forestry and Wildlife Management, Hedmark University College, Koppang, Norway Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Hybridization has been proposed as a mechanism by which exotic plants can increase their invasiveness. By generating novel recombinants, hybridization may result in phenotypes that are better adapted to the new environment than their parental species. We experimentally assessed the resistance of five exotic Fallopia taxa, F. japonica var. japonica , F. sachalinensis and F. baldschuanica , the two hybrids F. × bohemica and F. × conollyana , and the common European plants Rumex obtusifolius and Taraxacum officinale to four native European herbivores, the slug Arion lusitanicus, the moth Noctua pronuba , the grasshopper Metrioptera roeselii and the beetle Gastrophysa viridula. Leaf area consumed and relative growth rate of the herbivores differed significantly between the Fallopia taxa and the native species, as well as among the Fallopia taxa, and was partly influenced by interspecific variation in leaf morphology and physiology. Fallopia japonica , the most abundant Fallopia taxon in Europe, showed the highest level of resistance against all herbivores tested. The level of resistance of the hybrids compared to that of their parental species varied depending on hybrid taxon and herbivore species. Genotypes of the hybrid F. × bohemica varied significantly in herbivore resistance, but no evidence was found that hybridization has generated novel recombinants that are inherently better defended against resident herbivores than their parental species, thereby increasing the hybrid’s invasion success. In general, exotic Fallopia taxa showed higher levels of herbivore resistance than the two native plant species, suggesting that both parental and hybrid Fallopia taxa largely escape from herbivory in Europe. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2035-8 Authors Christine Krebs, CABI Europe-Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland Esther Gerber, CABI Europe-Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland Diethart Matthies, Faculty of Biology, Department of Plant Ecology, Philipps University Marburg, Karl-von-Frisch-Strasse, 35032 Marburg, Germany Urs Schaffner, CABI Europe-Switzerland, Rue des Grillons 1, 2800 Delémont, Switzerland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no studies have compared effects of wholesale replacement of a native by a nonnative species on subsidies that support consumers in adjacent habitats, nor quantified the magnitude of these effects. We examined whether streams invaded by nonnative brook trout ( Salvelinus fontinalis ) in two regions of the Rocky Mountains, USA, produced fewer emerging adult aquatic insects compared to paired streams with native cutthroat trout ( Oncorhynchus clarkii ), and whether riparian spiders that depend on these prey were less abundant along streams with lower total insect emergence. As predicted, emergence density was 36% lower from streams with the nonnative fish. Biomass of brook trout was higher than the cutthroat trout they replaced, but even after accounting for this difference, emergence was 24% lower from brook trout streams. More riparian spiders were counted along streams with greater total emergence across the water surface. Based on these results, we predicted that brook trout replacement would result in 6–20% fewer spiders in the two regions. When brook trout replace cutthroat trout, they reduce cross-habitat resource subsidies and alter ecosystem function in stream-riparian food webs, not only owing to increased biomass but also because traits apparently differ from native cutthroat trout. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2000-6 Authors Joseph R. Benjamin, Stream Ecology Center, Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA Kurt D. Fausch, Department of Fish, Wildlife, and Conservation Biology, and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO 80523, USA Colden V. Baxter, Stream Ecology Center, Department of Biological Sciences, Idaho State University, Pocatello, ID 83209-8007, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Snow cover has dramatic effects on the structure and functioning of Arctic ecosystems in winter. In the tundra, the subnivean space is the primary habitat of wintering small mammals and may be critical for their survival and reproduction. We have investigated the effects of snow cover and habitat features on the distributions of collared lemming ( Dicrostonyx groenlandicus ) and brown lemming ( Lemmus trimucronatus ) winter nests, as well as on their probabilities of reproduction and predation by stoats ( Mustela erminea ) and arctic foxes ( Vulpes lagopus ). We sampled 193 lemming winter nests and measured habitat features at all of these nests and at random sites at two spatial scales. We also monitored overwinter ground temperature at a subsample of nest and random sites. Our results demonstrate that nests were primarily located in areas with high micro-topography heterogeneity, steep slopes, deep snow cover providing thermal protection (reduced daily temperature fluctuations) and a high abundance of mosses. The probability of reproduction increased in collared lemming nests at low elevation and in brown lemming nests with high availability of some graminoid species. The probability of predation by stoats was density dependent and was higher in nests used by collared lemmings. Snow cover did not affect the probability of predation of lemming nests by stoats, but deep snow cover limited predation attempts by arctic foxes. We conclude that snow cover plays a key role in the spatial structure of wintering lemming populations and potentially in their population dynamics in the Arctic. Content Type Journal Article Pages 1-14 DOI 10.1007/s00442-011-2045-6 Authors David Duchesne, Département de Biologie, Centre d’Études Nordiques, Université Laval, 1045 Avenue de la Médecine, Quebec, QC G1V 0A6, Canada Gilles Gauthier, Département de Biologie, Centre d’Études Nordiques, Université Laval, 1045 Avenue de la Médecine, Quebec, QC G1V 0A6, Canada Dominique Berteaux, Canada Research Chair in Conservation of Northern Ecosystems, Centre d’Études Nordiques, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski, QC, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The cause(s) of the late Pleistocene megafauna extinction on the Australian continent remains largely unresolved. Unraveling climatic forcing mechanisms from direct or indirect human agents of ecosystem alteration has proven to be extremely difficult in Australia due to the lack of (1) well-dated vertebrate fossils and (2) paleo-environmental and -ecological records spanning the past approximately 100 ka when regional climatic conditions are known to have significantly varied. We have examined the nitrogen isotope composition (δ 15 N) of modern emu ( Dromaius novaehollandiae ) eggshells collected along a precipitation gradient in Australia, along with modern climatological data and dietary δ 15 N values. We then used modern patterns to interpret an approximately 130-ka record of δ 15 N values in extant Dromaius and extinct Genyornis newtoni eggshells from Lake Eyre to obtain a novel mean annual precipitation (MAP) record for central Australia spanning the extinction interval. Our data also provide the first detailed information on the trophic ecology and environmental preferences of two closely related taxa, one extant and one extinct. Dromaius eggshell δ 15 N values show a significant shift to higher values during the Last Glacial Maximum and Holocene, which we interpret to indicate more frequent arid conditions (〈200 mm MAP), relative to δ 15 N from samples just prior to the megafauna extinction. Genyornis eggshells had δ 15 N values reflecting wetter nesting conditions overall relative to those of coeval Dromaius , perhaps indicating that Genyornis was more reliant on mesic conditions. Lastly, the Dromaius eggshell record shows a significant decrease in δ 13 C values prior to the extinction, whereas the Genyornis record does not. Neither species showed a concomitant change in δ 15 N prior to the extinction, which suggests that a significant change in vegetation surrounding Lake Eyre occurred prior to an increase in local aridity. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2046-5 Authors Seth D. Newsome, Zoology and Physiology Department, University of Wyoming, 1000 East University Avenue, Department 3166, Laramie, WY 82071, USA Gifford H. Miller, Institute of Arctic and Alpine Research (INSTAAR), University of Colorado, Boulder, CO 80309-0450, USA John W. Magee, Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia Marilyn L. Fogel, Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A general prediction of the specialist/generalist paradigm indicates that plant responses to insect herbivores may depend on the degree of ecological specialization of the insect attacker. However, results from a single greenhouse experiment evaluating the responses of the model plant Arabidopsis thaliana to three specialist ( Plutella xylostella , Pieris rapae , and Brevicoryne brassicae ) and three generalist ( Trichoplusia ni , Spodoptera exigua , and Myzus persicae ) insect species did not support the previous prediction. Using an ecological genomic approach, we assessed plant responses in terms of herbivore-induced changes in genome-wide gene expression, defense-related pathways, and concentrations of glucosinolates (i.e., secondary metabolites that are ubiquitously present in cruciferous plants). Our results showed that plant responses were not influenced by the degree of specialization of insect herbivores. In contrast, responses were more strongly shaped by insect taxa (i.e., aphid vs. lepidopteran species), likely due to their different feeding modes. Interestingly, similar patterns of plant responses were induced by the same insect herbivore species in terms of defense signaling (jasmonic acid pathway), aliphatic glucosinolate metabolism (at both the gene expression and phenotypic levels) and genome-wide responses. Furthermore, plant responses to insect herbivores belonging to the same taxon (i.e., four lepidopteran species) were not explained by herbivore specialization or phylogenetic history. Overall, this study suggests that different feeding modes of insect taxa as well as herbivore-specific plant responses, which may result from distinct ecological/evolutionary interactions between A. thaliana (or a close relative) and each of the lepidopteran species, may explain why observed responses deviate from those predicted by the specialist/generalist paradigm. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2015-z Authors M. Gabriela Bidart-Bouzat, Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43402, USA Daniel Kliebenstein, Department of Plant Sciences, University of California, Davis, CA 95616, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Epizootics of nucleopolyhedrovirus characterize declines of cyclic populations of western tent caterpillars, Malacosoma pluviale californicum. In field populations, infection can be apparently lacking in one generation and high in the next. This may suggest an increase in the susceptibility to infection of larvae at peak density or the triggering of a vertically transmitted virus. Here, we test the hypothesis that reduced food availability, as may occur during population outbreaks of tent caterpillars, influences the immunocompetence of larvae and increases their susceptibility to viral infection. We compared immunity factors, hemolymph phenoloxidase and hemocyte numbers, and the susceptibility to nucleopolyhedroviral infection of fifth instar larvae that were fully or partially fed as fourth instars. To determine if maternal or transgenerational influences occurred, we also determined the susceptibility of the offspring of the treated parents to viral infection. Food limitation significantly reduced larval survival, development rate, larval and pupal mass, moth fecundity and levels of hemolymph phenoloxidase, but not the numbers of hemocytes. Neither the food-reduced larvae nor their offspring were more susceptible to viral infection and were possibly even less susceptible at intermediate viral doses. Food reduction did not activate latent or covert viral infection of larvae as might be expected as a response to stress. We conclude that reducing the food intake of fourth instar larvae to an extent that had measurable and realistic impacts on their life history characteristics was not translated into increased susceptibility to viral infection. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2023-z Authors Judith H. Myers, Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada Jenny S. Cory, Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada Jerry D. Ericsson, Department of Biological Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada Michelle L. Tseng, Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Sphagnum mosses are widespread in areas where mires exist and constitute a globally important carbon sink. Their ecophysiology is known to be related to the water level, but very little is currently known about the successional trend in Sphagnum . We hypothesized that moss species follow the known vascular plant growth strategy along the successional gradient (i.e., decrease in production and maximal photosynthesis while succession proceeds). To address this hypothesis, we studied links between the growth and related ecophysiological processes of Sphagnum mosses from a time-since-initiation chronosequence of five wetlands. We quantified the rates of increase in biomass and length of different Sphagnum species in relation to their CO 2 assimilation rates, their photosynthetic light reaction efficiencies, and their physiological states, as measured by the chlorophyll fluorescence method. In agreement with our hypothesis, increase in biomass and CO 2 exchange rate of Sphagnum mosses decreased along the successional gradient, following the tactics of more intensely studied vascular plants. Mosses at the young and old ends of the chronosequence showed indications of downregulation, measured as a low ratio between variable and maximum fluorescence ( F v / F m ). Our study divided the species into three groups; pioneer species, hollow species, and ombrotrophic hummock formers. The pioneer species S. fimbriatum is a ruderal plant that occurred at the first sites along the chronosequence, which were characterized by low stress but high disturbance. Hollow species are competitive plants that occurred at sites with low stress and low disturbance (i.e., in the wet depressions in the middle and at the old end of the chronosequence). Ombrotrophic hummock species are stress-tolerant plants that occurred at sites with high stress and low disturbance (i.e., at the old end of the chronosequence). The three groups along the mire successional gradient appeared to be somewhat analogous to the three primary strategies suggested by Grime. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2039-4 Authors Anna M. Laine, Department of Biology, University of Oulu, Oulu, Finland Eija Juurola, Department of Forest Science, University of Helsinki, Helsinki, Finland Tomáš Hájek, Institute of Botany, Czech Academy of Sciences, Třeboň, Czech Republic Eeva-Stiina Tuittila, Department of Forest Science, University of Helsinki, Helsinki, Finland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Legacy effects occur when particular species or their interactions with others have long-lasting impacts, and they are increasingly recognized as important determinants of ecological processes. However, when such legacy effects have been explicitly explored, they most often involve the long-term direct effects of species on systems, as opposed to the indirect effects. Here, we explore how a legacy of small mammal exclusion on the abundance of a shrub, bush lupine ( Lupinus arboreus ), influences the abundance of a native land snail ( Helminthoglypta arrosa ) in coastal prairie and dune habitats in central California. The factors that limit populations of land snails are very poorly known despite the threats to the persistence of this group of species. In grasslands, prior vole ( Microtus californicus ) exclusion created long-lasting gains in bush lupine abundance, mediated through the seedbank, and was associated with increased snail numbers (10×) compared to control plots where mammals were never excluded. Similar plots in dune habitat showed no difference in snail numbers due to previous mammal exclusion. We tested whether increased competition for food, increased predation, and/or lower desiccation explained the decline in snail numbers in plots with reduced lupine cover. Tethering experiments supported the hypothesis that voles can have long-lasting impacts as ecosystem engineers, reducing woody lupine habitat required for successful aestivation by snails. These results add to a growing list of studies that have found that non-trophic interactions can be limiting to invertebrate consumers. Content Type Journal Article Pages 1-7 DOI 10.1007/s00442-011-2054-5 Authors Mikaela Huntzinger, Center for Excellence in Teaching and Learning, University of California, Davis, CA 95616, USA Richard Karban, Department of Entomology, University of California, Davis, CA 95616, USA John L. Maron, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plant invasions can have substantial consequences for the soil ecosystem, altering microbial community structure and nutrient cycling. However, relatively little is known about what drives these changes, making it difficult to predict the effects of future invasions. In addition, because most studies compare soils from uninvaded areas to long-established dense invasions, little is known about the temporal dependence of invasion impacts. We experimentally manipulated forest understory vegetation in replicated sites dominated either by exotic Japanese barberry ( Berberis thunbergii) , native Viburnums , or native Vacciniums , so that each vegetation type was present in each site-type. We compared the short-term effect of vegetation changes to the lingering legacy effects of the previous vegetation type by measuring soil microbial community structure (phospholipid fatty acids) and function (extracellular enzymes and nitrogen mineralization). We also replaced the aboveground litter in half of each plot with an inert substitute to determine if changes in the soil microbial community were driven by aboveground or belowground plant inputs. We found that after 2 years, the microbial community structure and function was largely determined by the legacy effect of the previous vegetation type, and was not affected by the current vegetation. Aboveground litter removal had only weak effects, suggesting that changes in the soil microbial community and nutrient cycling were driven largely by belowground processes. These results suggest that changes in the soil following either invasion or restoration do not occur quickly, but rather exhibit long-lasting legacy effects from previous belowground plant inputs. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2022-0 Authors Kenneth J. Elgersma, Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA Joan G. Ehrenfeld, Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA Shen Yu, Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA Torsten Vor, Department of Ecology, Evolution, and Natural Resources, Rutgers University, New Brunswick, NJ, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Biogeochemical theory emphasizes nitrogen (N) limitation and the many factors that can restrict N accumulation in temperate forests, yet lacks a working model of conditions that can promote naturally high N accumulation. We used a dynamic simulation model of ecosystem N and δ 15 N to evaluate which combination of N input and loss pathways could produce a range of high ecosystem N contents characteristic of forests in the Oregon Coast Range. Total ecosystem N at nine study sites ranged from 8,788 to 22,667 kg ha −1 and carbon (C) ranged from 188 to 460 Mg ha −1 , with highest values near the coast. Ecosystem δ 15 N displayed a curvilinear relationship with ecosystem N content, and largely reflected mineral soil, which accounted for 96–98% of total ecosystem N. Model simulations of ecosystem N balances parameterized with field rates of N leaching required long-term average N inputs that exceed atmospheric deposition and asymbiotic and epiphytic N 2 -fixation, and that were consistent with cycles of post-fire N 2 -fixation by early-successional red alder. Soil water δ 15 NO 3 − patterns suggested a shift in relative N losses from denitrification to nitrate leaching as N accumulated, and simulations identified nitrate leaching as the primary N loss pathway that constrains maximum N accumulation. Whereas current theory emphasizes constraints on biological N 2 -fixation and disturbance-mediated N losses as factors that limit N accumulation in temperate forests, our results suggest that wildfire can foster substantial long-term N accumulation in ecosystems that are colonized by symbiotic N 2 -fixing vegetation. Content Type Journal Article Pages 1-15 DOI 10.1007/s00442-011-2016-y Authors Steven S. Perakis, Forest and Rangeland Ecosystem Science Center, U.S. Geological Survey, Corvallis, OR 97331, USA Emily R. Sinkhorn, Department of Forest Ecosystems and Society, Oregon State University, Corvallis, OR 97331, USA Jana E. Compton, Western Ecology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Corvallis, OR 97333, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    We have studied how disturbance by ploughing and rotavation affects the carbon (C) flow to arbuscular mycorrhizal (AM) fungi in a dry, semi-natural grassland. AM fungal biomass was estimated using the indicator neutral lipid fatty acid (NLFA) 16:1ω5, and saprotrophic fungal biomass using NLFA 18:2ω6,9. We labeled vegetation plots with 13 CO 2 and studied the C flow to the signature fatty acids as well as uptake and allocation in plants. We found that AM fungal biomass in roots and soil decreased with disturbance, while saprotrophic fungal biomass in soil was not influenced by disturbance. Rotavation decreased the 13 C enrichment in NLFA 16:1ω5 in soil, but 13 C enrichment in the AM fungal indicator NLFA 16:1ω5 in roots or soil was not influenced by any other disturbance. In roots, 13 C enrichment was consistently higher in NLFA 16:1ω5 than in crude root material. Grasses (mainly Festuca brevipila ) decreased as a result of disturbance, while non-mycorrhizal annual forbs increased. This decreases the potential for mycorrhizal C sequestration and may have been the main reason for the reduced mycorrhizal C allocation found in disturbed plots. Disturbance decreased the soil ammonium content but did not change the pH, nitrate or phosphate availability. The overall effect of disturbance on C allocation was that more of the C in AM fungal mycelium was directed to the external phase. Furthermore, the functional identity of the plants seemed to play a minor role in the C cycle as no differences were seen between different groups, although annuals contained less AM fungi than the other groups. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2020-2 Authors Tim Krone Schnoor, Plant Ecology and Systematics, Department of Biology, Lund University, The Ecology Building, Sölvegatan 47, 223 62 Lund, Sweden Linda-Maria Mårtensson, Plant Ecology and Systematics, Department of Biology, Lund University, The Ecology Building, Sölvegatan 47, 223 62 Lund, Sweden Pål Axel Olsson, Plant Ecology and Systematics, Department of Biology, Lund University, The Ecology Building, Sölvegatan 47, 223 62 Lund, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Nutrient availability and herbivory can regulate primary production in ecosystems, but little is known about how, or whether, they may interact with one another. Here, we investigate how nitrogen availability and insect herbivory interact to alter aboveground and belowground plant community biomass in an old-field ecosystem. In 2004, we established 36 experimental plots in which we manipulated soil nitrogen (N) availability and insect abundance in a completely randomized plot design. In 2009, after 6 years of treatments, we measured aboveground biomass and assessed root production at peak growth. Overall, we found a significant effect of reduced soil N availability on aboveground biomass and belowground plant biomass production. Specifically, responses of aboveground and belowground community biomass to nutrients were driven by reductions in soil N, but not additions, indicating that soil N may not be limiting primary production in this ecosystem. Insects reduced the aboveground biomass of subdominant plant species and decreased coarse root production. We found no statistical interactions between N availability and insect herbivory for any response variable. Overall, the results of 6 years of nutrient manipulations and insect removals suggest strong bottom-up influences on total plant community productivity but more subtle effects of insect herbivores on aspects of aboveground and belowground production. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2028-7 Authors Jarrod D. Blue, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37796, USA Lara Souza, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37796, USA Aimée T. Classen, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37796, USA Jennifer A. Schweitzer, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37796, USA Nathan J. Sanders, Department of Ecology and Evolutionary Biology, University of Tennessee, 569 Dabney Hall, Knoxville, TN 37796, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Indirect resource competition and interference are widely occurring mechanisms of interspecific interactions. We have studied the seasonal expression of these two interaction types within a two-species, boreal small mammal system. Seasons differ by resource availability, individual breeding state and intraspecific social system. Live-trapping methods were used to monitor space use and reproduction in 14 experimental populations of bank voles Myodes glareolus in large outdoor enclosures with and without a dominant competitor, the field vole Microtus agrestis. We further compared vole behaviour using staged dyadic encounters in neutral arenas in both seasons. Survival of the non-breeding overwintering bank voles was not affected by competition. In the spring, the numbers of male bank voles, but not of females, were reduced significantly in the competition populations. Bank vole home ranges expanded with vole density in the presence of competitors, indicating food limitation. A comparison of behaviour between seasons based on an analysis of similarity revealed an avoidance of costly aggression against opponents, independent of species. Interactions were more aggressive during the summer than during the winter, and heterospecific encounters were more aggressive than conspecific encounters. Based on these results, we suggest that interaction types and their respective mechanisms are not either–or categories and may change over the seasons. During the winter, energy constraints and thermoregulatory needs decrease direct aggression, but food constraints increase indirect resource competition. Direct interference appears in the summer, probably triggered by each individual’s reproductive and hormonal state and the defence of offspring against conspecific and heterospecific intruders. Both interaction forms overlap in the spring, possibly contributing to spring declines in the numbers of subordinate species. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2008-y Authors Jana A. Eccard, Unit of Animal Ecology, University of Potsdam, Maulbeerallee 1, 14469 Potsdam, Germany Karen Fey, Institute of Ecology, Friedrich-Schiller-University Jena, 07743 Jena, Germany Barbara A. Caspers, Department of Behavioural Biology, Research Group of Molecular Ecology and Behaviour, University of Bielefeld, Morgenbreede 45, 33615 Bielefeld, Germany Hannu Ylönen, Department of Biological and Environmental Science, Konnevesi Research Station, University of Jyväskylä, P.O. Box 35 (Ambiotica), 40014 Jyväskylä, Finland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Optimization theory in combination with canopy modeling is potentially a powerful tool for evaluating the adaptive significance of photosynthesis-related plant traits. Yet its successful application has been hampered by a lack of agreement on the appropriate optimization criterion. Here we review how models based on different types of optimization criteria have been used to analyze traits—particularly N reallocation and leaf area indices—that determine photosynthetic nitrogen-use efficiency at the canopy level. By far the most commonly used approach is static-plant simple optimization (SSO). Static-plant simple optimization makes two assumptions: (1) plant traits are considered to be optimal when they maximize whole-stand daily photosynthesis, ignoring competitive interactions between individuals; (2) it assumes static plants, ignoring canopy dynamics (production and loss of leaves, and the reallocation and uptake of nitrogen) and the respiration of nonphotosynthetic tissue. Recent studies have addressed either the former problem through the application of evolutionary game theory (EGT) or the latter by applying dynamic-plant simple optimization (DSO), and have made considerable progress in our understanding of plant photosynthetic traits. However, we argue that future model studies should focus on combining these two approaches. We also point out that field observations can fit predictions from two models based on very different optimization criteria. In order to enhance our understanding of the adaptive significance of photosynthesis-related plant traits, there is thus an urgent need for experiments that test underlying optimization criteria and competing hypotheses about underlying mechanisms of optimization. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2011-3 Authors Niels P. R. Anten, Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands Heinjo J. During, Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Evaluating the response of organisms to stress assumes that functional benchmarks are available against which the response can be gauged, but this expectation remains unfulfilled for many taxa. As a result, attempts to describe the organismic effects of environmental degradation and physiological stress can prove misleading. Functional benchmarks and the effects of stress are particularly germane to coral reefs that globally are exposed to significant environmental challenges, and in this study, we compiled data on scleractinian corals to describe a reference against which stress responses can be gauged. Based on this construct, we tested the veracity of well-established contrasts––involving differences in physiological function among depths and families––to evaluate the capacity of available data to support synthetic analyses. Our analysis used 126 papers describing 37 genera, and at least 73 species, and described 13 traits, first independent of depth, and second, by depth. Data appropriate for these analyses were so sparse that depth- and family-level effects were inconspicuous, although the depth contrast revealed a decline in dark respiration and an increase in calcification (both normalized to area) in deeper water. Our analyses of scleractinian literature revealed limitations of the data available for synthetic analyses, as well for describing functional benchmarks within this taxon. We attribute some of these effects to differences in the physical environment under which measurements were made, and suspect that such problems are commonplace for other taxa. Dynamic Energy Budget (DEB) models provide one means to overcome some of these problems, and they can be used for any taxon to quantitatively summarize data for comparative analyses of stressor responses. The suitability of these models is illustrated for scleractinian corals by predicting from first principles the ratio of Symbiodinium to holobiont carbon and the respiration. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2004-2 Authors Peter J. Edmunds, Department of Biology, California State University, 18111 Nordhoff Street, Northridge, CA 91330-8303, USA Hollie M. Putnam, Hawaii Institute of Marine Biology, School of Earth and Science and Technology, University of Hawaii, 46-007 Lilipuna Road, Kaneohe, HI 96744, USA Roger M. Nisbet, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106-9610, USA Erik B. Muller, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106-9610, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Organisms frequently need to adjust physiological mechanisms to successfully breed in novel habitats. To explore how some populations physiologically acclimate to novel environmental conditions while others do not, we examine three subspecies of the white-crowned sparrow, Zonotrichia leucophrys . Of these subspecies, Z. l. pugetensis has expanded its breeding range to high altitude over the last 60 years. We investigate physiological acclimation to high altitude conditions by comparing circulating levels of glucocorticoids among Z. l. gambelii , which only breeds at high altitude, Z. l. nuttalli , which only breeds at low altitude, a population of Z. l. pugetensis that breeds at low altitude, and a Z. l. pugetensis population that now breeds at high altitude. Glucocorticoids mediate physiological and behavioral responses to environmental conditions and are constitutively secreted, but can also be released facultatively. We hypothesized that elevation of the glucocorticoid corticosterone (CORT) may facilitate breeding in high altitude environments. We tested this hypothesis by comparing baseline and stress-induced CORT levels of subspecies breeding at low altitude, Z. l. pugetensis and Z. l. nuttalli , to subspecies breeding at high altitude, Z. l. pugetensis and Z. l. gambelii . We found that populations breeding at high altitude exhibit higher baseline and stress-induced levels of CORT. Additionally, we found that Z. l. pugetensis exhibit greater variation in the stress-induced CORT response. These results suggest an importance of modulation of hormonal mechanisms in facilitating breeding in high altitude environments, and that variation in these mechanisms may be associated with facilitating altitudinal range expansion. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2001-5 Authors Elizabeth A. Addis, Department of Biology, University of Washington, Seattle, WA 98105, USA Jason E. Davis, Department of Biology, University of Washington, Seattle, WA 98105, USA Brooks E. Miner, Department of Biology, University of Washington, Seattle, WA 98105, USA John C. Wingfield, Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA 95616, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Forest fragmentation may benefit generalist herbivores by increasing access to various substitutable food resources, with potential consequences for their population dynamics. We studied a European roe deer ( Capreolus capreolus ) population living in an agricultural mosaic of forest, woodlots, meadows and cultivated crops. We tested whether diet composition and quality varied spatially across the landscape using botanical analyses of rumen contents and chemical analyses of the plants consumed in relation to landscape metrics. In summer and non-mast winters, roe deer ate more cultivated seeds and less native forest browse with increasing availability of crops in the local landscape. This spatial variation resulted in contrasting diet quality, with more cell content and lower lignin and hemicellulose content (high quality) for individuals living in more open habitats. The pattern was less marked in the other seasons when diet composition, but not diet quality, was only weakly related to landscape structure. In mast autumns and winters, the consumption of acorns across the entire landscape resulted in a low level of differentiation in diet composition and quality. Our results reflect the ability of generalist species, such as roe deer, to adapt to the fragmentation of their forest habitat by exhibiting a plastic feeding behavior, enabling them to use supplementary resources available in the agricultural matrix. This flexibility confers nutritional advantages to individuals with access to cultivated fields when their native food resources are depleted or decline in quality (e.g. during non-mast years) and may explain local heterogeneities in individual phenotypic quality. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1994-0 Authors Frial Abbas, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Nicolas Morellet, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France A. J. Mark Hewison, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Joël Merlet, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Bruno Cargnelutti, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Bruno Lourtet, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Jean-Marc Angibault, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Tanguy Daufresne, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Stéphane Aulagnier, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Hélène Verheyden, INRA-CEFS, Comportement et Ecologie de la Faune Sauvage, Institut National de la Recherche Agronomique, BP 52627, 31326 Castanet-Tolosan Cedex, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    An understanding of foraging behavior is crucial to understanding higher level community dynamics; in particular, there is a lack of information about how different species discover food resources. We examined the effect of forager number and forager discovery capacity on food discovery in two disparate temperate ant communities, located in Texas and Arizona. We defined forager discovery capacity as the per capita rate of resource discovery, or how quickly individual ants arrived at resources. In general, resources were discovered more quickly when more foragers were present; this was true both within communities, where species identity was ignored, as well as within species. This pattern suggests that resource discovery is a matter of random processes, with ants essentially bumping into resources at a rate mediated by their abundance. In contrast, species that were better discoverers, as defined by the proportion of resources discovered first, did not have higher numbers of mean foragers. Instead, both mean forager number and mean forager discovery capacity determined discovery success. The Texas species used both forager number and capacity, whereas the Arizona species used only forager capacity. There was a negative correlation between a species’ prevalence in the environment and the discovery capacity of its foragers, suggesting that a given species cannot exploit both high numbers and high discovery capacity as a strategy. These results highlight that while forager number is crucial to determining time to discovery at the community level and within species, individual forager characteristics influence the outcome of exploitative competition in ant communities. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-1982-4 Authors Jessica M. C. Pearce-Duvet, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Martin Moyano, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Frederick R. Adler, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Donald H. Feener, Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The predicted increase in atmospheric CO 2 concentration for this century is expected to lead to increases in temperature and changes in litter quality that can affect small woodland streams, where water temperature is usually low and allochthonous organic matter constitutes the basis of the food web. We have assessed the individual and interactive effect of water temperature (5 and 10°C) and alder litter quality produced under ambient CO 2 levels (ambient litter) or under CO 2 concentrations predicted for 2050 (elevated litter) on litter decomposition and on fungal activity and assemblage structure. Litter decomposition rates and fungal respiration rates were significantly faster at 10 than at 5°C, but they were not affected by litter quality. Litter quality affected mycelial biomass accrual at 5 but not at 10°C, while increases in temperature stimulated biomass accrual on ambient but not on elevated litter. A similar pattern was observed for conidial production. All variables were stimulated on elevated litter at 10°C (future scenario) compared with ambient litter at 5°C (present scenario), but interactions between temperature and litter quality were additive. Temperature was the factor that most strongly affected the structure of aquatic hyphomycete assemblages. Our results indicate that if future increases in atmospheric CO 2 lead to only slight modifications in litter quality, the litter decomposition and fungal activities and community structure will be strongly controlled by increased water temperature. This may have serious consequences for aquatic systems as faster litter decomposition may lead to food depletion for higher trophic levels. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-1976-2 Authors Verónica Ferreira, IMAR-CMA, Department of Life Sciences, University of Coimbra, P.O. Box 3046-401, Coimbra, Portugal Eric Chauvet, UPS, INPT; EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), Université de Toulouse 3–Université Paul Sabatier, Bâtiment 4R1, 31062 Toulouse, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Because nutrient enrichment can increase ecosystem productivity, it may enhance resource flows to adjacent ecosystems as organisms cross ecosystem boundaries and subsidize predators in recipient ecosystems. Here, we quantified the biomass and abundance of aquatic emergence and terrestrial spiders in a reference and treatment stream that had been continuously enriched with nitrogen and phosphorus for 5 years. Because we previously showed that enrichment increased secondary production of stream consumers, we predicted that aquatic emergence flux would be higher in the treatment stream, subsequently increasing the biomass and abundance of terrestrial spiders. Those increases were predicted to be greatest for spiders specializing on aquatic emergence subsidies (e.g., Tetragnathidae). By adding a 15 N stable isotope tracer to both streams, we also quantified nitrogen flow from the stream into the riparian community. Emergence biomass, but not abundance, was higher in the treatment stream. The average body size of emerging adult insects and the relative dominance of Trichoptera adults were also greater in the treatment stream. However, spider biomass did not differ between streams. Spiders also exhibited substantially lower reliance on aquatic emergence nitrogen in the treatment stream. This reduced reliance likely resulted from shifts in the body size distributions and community composition of insect emergence that may have altered predator consumption efficiency in the treatment stream. Despite nutrient enrichment approximately doubling stream productivity and associated cross-ecosystem resource flows, the response of terrestrial predators depended more on the resource subsidy’s characteristics that affected the predator’s ability to capitalize on such increases. Content Type Journal Article Pages 1-14 DOI 10.1007/s00442-011-2026-9 Authors John M. Davis, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA Amy D. Rosemond, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA Gaston E. Small, Odum School of Ecology, University of Georgia, Athens, GA 30602, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The island syndrome predicts directional changes in the morphology and demography of insular vertebrates, due to changes in trophic complexity and migration rates caused by island size and isolation. However, the high rate of human-mediated species introductions to some islands also increases trophic complexity, and this will reduce the perceived insularity on any such island. We test four hypotheses on the role of increased trophic complexity on the island syndrome, using introduced black rats ( Rattus rattus ) on two isolated coral atolls in the Mozambique Channel. Europa Island has remained relatively pristine and insular, with few species introductions, whereas Juan de Nova Island has had many species introductions, including predators and competitors of rats, anthropogenically increasing its trophic complexity. In the most insular environments, the island syndrome is expected to generate increases in body size and densities of rodents but decreases in the rates of reproduction and population cycling. Morphology and reproduction were compared using linear regression and canonical discriminant analysis, while density and population cycling were compared using spatially explicit capture–recapture analysis. Results were compared to other insular black rat populations in the Mozambique Channel and were consistent with predictions from the island syndrome. The manifestation of an island syndrome in rodents depends upon the trophic composition of a community, and may not relate to island size alone when many species additions, such as invasions, have occurred. The differing patterns of rodent population dynamics on each island provide information for future rodent eradication operations. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2031-z Authors James C. Russell, ECOMAR, Université de la Réunion, 15 avenue René Cassin, 97715 Saint Denis, France David Ringler, ECOMAR, Université de la Réunion, 15 avenue René Cassin, 97715 Saint Denis, France Aurélien Trombini, ECOMAR, Université de la Réunion, 15 avenue René Cassin, 97715 Saint Denis, France Matthieu Le Corre, ECOMAR, Université de la Réunion, 15 avenue René Cassin, 97715 Saint Denis, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Dominance of invasive species is often assumed to be due to a superior ability to acquire resources. However, dominance in plant communities can arise through multiple interacting mechanisms, including disturbance. Inter-specific competition can be strongly affected by abiotic conditions, which can determine the outcome of competitive interactions. We evaluated competition and disturbance as mechanisms governing dominance of Phyla canescens (hereafter lippia), an invasive perennial forb from South America, in Paspalum distichum (perennial grass, hereafter water couch) meadows in floodplain wetlands of eastern Australia. Water couch meadows (in the study area) are listed under the Ramsar Convention due to their significance as habitat for migratory waterbirds. In the field, we monitored patterns of vegetation boundaries between the two species in response to flooding. Under controlled glasshouse conditions, we explored competitive interactions between the native water couch and lippia subject to different soil moisture/inundation regimes. We did this using a pairwise factorial glasshouse experiment that manipulated neighbor density (9 treatments) and soil moisture/inundation (4 treatments). In the field trial, inundation increased the cover of water couch. Under more controlled conditions, the invader had a competitive effect on the native species only under dry soil conditions, and was strongly inhibited by inundation. This suggests that dry conditions favor the growth of the invader and wetter (more historical) conditions favor the native grass. In this system, invader dominance is governed by altered disturbance regimes which give the invader a competitive advantage over the native species. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2027-8 Authors J. N. Price, Ecosystem Management, University of New England, Armidale, NSW 2351, Australia P. J. Berney, Ecosystem Management, University of New England, Armidale, NSW 2351, Australia D. Ryder, Ecosystem Management, University of New England, Armidale, NSW 2351, Australia R. D. B. Whalley, Department of Botany, University of New England, Armidale, NSW 2351, Australia C. L. Gross, Ecosystem Management, University of New England, Armidale, NSW 2351, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Trophic interactions can trigger the development of exaggerated specialized characters and promote morphological diversification. For example, acorn weevils (genus Curculio ) present strikingly long rostrums, which are used by females to perforate oviposition holes through the seed coat. Species exhibiting longer rostrums are known to exploit larger acorns, and therefore rostrum length is thought to be subject to selection to match the preferred acorn type. However, rostrum length is strongly correlated with body size, and morphological divergence could result from either selection on rostrum length for optimal food exploitation or from other pressures acting on body size. We collected infested acorns at oak forests where the large Curculio elephas and the small-bodied Curculio glandium co-occur. There were no interspecific differences in adult female body size to rostrum length allometric relationships, and rostrum length is equally correlated with body size in either species. MtDNA-based species identification showed that C. glandium larvae were present within acorns of all sizes, whereas C. elephas larvae were restricted to acorns above a minimum size, irrespective of oak species. Hence, exploitation of large acorns can hardly have triggered rostrum enlargement, as the small sized C. glandium adults (with short rostrums) could perforate and oviposit in both small and large acorns. Rather, increased rostrum length is probably a by-product of the larger body sizes of individuals emerging from bigger acorns, which allow increased larval size and enhance larval survival likelihood. Summarizing, when exaggerated feeding traits co-vary with other body features, interspecific morphological variability may result from contrasting selective pressures acting on these correlated characters. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2036-7 Authors Raul Bonal, Department of Entomology, Natural History Museum, Cromwell Road, London, SW7 5BD UK Josep Maria Espelta, Centre for Ecological Research and Forestry Applications (CREAF), Autonomous University of Barcelona, 08193 Bellaterra (Catalonia), Spain Alfried P. Vogler, Department of Entomology, Natural History Museum, Cromwell Road, London, SW7 5BD UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    It is widely accepted that stable isotope ratios in inert tissues such as feather keratin reflect the dietary isotopic signature at the time of the tissue synthesis. However, some elements such as stable nitrogen isotopes can be affected by individual physiological state and nutritional stress. Using malaria infection experiment protocols, we estimated the possible effect of malaria parasite infections on feather carbon (δ 13 C) and nitrogen (δ 15 N) isotope signatures in juvenile common crossbills Loxia curvirostra . The birds were experimentally infected with Plasmodium relictum (lineage SGS1) and P. ashfordi (GRW2), two widespread parasites of passerines. Experimental birds developed heavy parasitemia of both parasites and maintained high levels throughout the experiment (33 days). We found no significant difference between experimental and control birds in both δ 13 C and δ 15 N values of feathers re-grown. The study shows that even heavy primary infections of malaria parasites do not affect feather δ 13 C and δ 15 N isotopic signatures. The results of this experiment demonstrate that feather isotope values of wild-caught birds accurately reflect the dietary isotopic sources at the time of tissue synthesis even when the animal’s immune system might be challenged due to parasitic infection. Content Type Journal Article Pages 1-6 DOI 10.1007/s00442-011-2041-x Authors Elizabeth Yohannes, Stable Isotope Laboratory, Institute for Limnology, University of Constance, 78464 Constance, Germany Vaidas Palinauskas, Nature Research Centre, Akademijos 2, Vilnius 21, LT 08412, Lithuania Gediminas Valkiūnas, Nature Research Centre, Akademijos 2, Vilnius 21, LT 08412, Lithuania Raymond W. Lee, School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA Casimir V. Bolshakov, Biological Station “Rybachy” of the Zoological Institute, Russian Academy of Sciences, Rybachy, 238535 Kaliningrad Reg, Russia Staffan Bensch, Molecular Ecology and Evolution Lab, Department of Biology, Lund University, Ecology Building, 22362 Lund, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Specific leaf area (SLA) is a key functional trait reflecting the trade-off between resource capture and conservation, and has been identified as playing an important role in plant community assembly. Mechanistic models of community assembly state that the assemblage of species in a local community is controlled by environment filters operating on functional traits. We measured within- and among-species variation of SLA, and environmental conditions in a tropical cloud forest to explore how variation in this functional trait contributes to community assembly. SLA variation at the species level was also decomposed into alpha (within assemblage variation), and beta (across assemblage variation) values. SLA decreased with increasing solar irradiance (approximated using plant height) within the three study sites, and differed among the three sites both for within- and among-species comparisons. Mean plot SLA, accounting for both within and among species across the three sites, increased significantly in relation to air temperature but not local photosynthetic photon flux density and soil total phosphorus. Alpha SLA decreased with increasing solar irradiance within the three sites and beta SLA differed among the three sites. Our results clearly demonstrate that light and air temperature are key environmental factors involved in organizing plant species within and among communities in tropical cloud forests. The strong relationship between both intra- and interspecific variation in SLA and environmental conditions strongly confirms the role of trait variation in the assembly of plant species in tropical cloud forest communities via environment filtering related to light availability and air temperature. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2050-9 Authors Wenxing Long, Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Haidian District, Beijing, 100091 China Runguo Zang, Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Haidian District, Beijing, 100091 China Brandon S. Schamp, Department of Biology, Algoma University, Sault Ste. Marie, ON P6A 2G4, Canada Yi Ding, Key Laboratory of Forest Ecology and Environment of State Forestry Administration, Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Haidian District, Beijing, 100091 China Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Bimodal distributions in plant size, with a major mode of small and minor mode of large-size plants, have been reported for a range of single species stands in different growing conditions. The occurrence of bimodality has implications for the dynamics of competition within a stand and potentially for stand productivity. However, deduction of the existence of bimodality has been by visual assessment of histograms of a single measure of plant size which can lead to differences of opinion about its existence. We show that the bivariate distribution of plant height and weight is more informative about stand structure than univariate distributions. We demonstrate how sub-populations of small- and large-size plants can be identified using a bivariate mixture distribution fitted using evolutionary computation. For the multiple datasets we analyse, a bimodal distribution fits in preference to unimodal or trimodal distributions. Small- and large-plant sub-populations, respectively, form a lower and upper canopy. The numbers of plants in these canopies change during stand development and vary with initial spacing, contrary to reports for other species. Early in stand development, large plants show spatial separation between themselves but spatial association with small plants, and as stands develop the number of large plants declines markedly but they remain spatially separated between each other. Bivariate analysis of height and weight, and spatial analysis of individuals of different sizes, provides a more comprehensive description of stand structure than that obtained in previous studies. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2048-3 Authors Marianne C. Turley, 3704 NE 22nd Avenue, Portland, OR 97212, USA E. David Ford, School of Forest Resources, University of Washington, Box 352100, Seattle, WA 98195-2100, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    An ecosystem containing a mixture of species that differ in phenology, morphology, and physiology might be expected to resist leaching of soil nutrients to a greater extent than one composed of a single species. We tested the effects of species identity and plant-life-form richness on nutrient leaching at a lowland tropical site where deep infiltration averages 〉2 m year −1 . Three indigenous tree species with contrasting leafing phenologies (evergreen, dry-season deciduous, and wet-season deciduous) were grown in monoculture and together with two other life-forms with which they commonly occur in tropical forests: a palm and a giant, perennial herb. To calculate nutrient leaching over an 11-year period, concentrations of nutrients in soil water were multiplied by drainage rates estimated from a water balance. The effect of plant-life-form richness on retention differed according to tree species identity and nutrient. Nitrate retention was greater in polycultures of the dry-season deciduous tree species (mean of 7.4 kg ha −1 year −1 of NO 3 –N lost compared to 12.7 in monoculture), and calcium and magnesium retention were greater in polycultures of the evergreen and wet-season deciduous tree species. Complementary use of light led to intensification of soil exploitation by roots, the main agent responsible for enhanced nutrient retention in some polycultures. Other mechanisms included differences in nutrient demand among species, and avoidance of catastrophic failure due to episodic weather events or pest outbreaks. Even unrealistically simple multi-life-form mimics of tropical forest can safeguard a site’s nutrient capital if careful attention is paid to species’ characteristics and temporal changes in interspecific interactions. Content Type Journal Article Pages 1-14 DOI 10.1007/s00442-011-2052-7 Authors John J. Ewel, Department of Biology, University of Florida, Gainesville, FL 32611, USA Seth W. Bigelow, USDA-FS Pacific Southwest Research Station, 1731 Research Park Drive, Davis, CA 95618, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The extent to which a plant assemblage might recolonize a disturbed system is in general related to the availability of propagule sources and sites with appropriate conditions for establishment. Both these factors might be sensitive to aspects of spatial heterogeneity. Microtopographic variation may enhance initial resistance by reducing the impact of the disturbance and facilitating establishment of incoming propagules by providing shaded “safe-sites”. This study explores the influence of microtopographic heterogeneity (caused by variation in surface boulder cover) on the recolonization of closed-canopy forest floor bryophytes using a chronosequence of 75 spruce-dominated forests in south-central Sweden (2–163 years after clear-cutting). We found that high boulder cover did increase survival and subsequent persistence in young forests at both investigated scales (i.e. 1,000 and 100 m 2 ), although this pattern became less evident on the smaller spatial scale. Species accumulation in boulder-poor subplots was not different when surrounded by boulder-rich compared with boulder-poor subplots suggesting short-distance recolonization from boulder-created refugia to be of little importance during recolonization. To conclude, it seems that boulders increase initial resistance to clear-cutting for this bryophyte guild, but that the subsequent recolonization process is more likely to depend on external propagule sources and factors affecting establishment such as the microclimate in the developing stand. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2049-2 Authors Martin Schmalholz, Department of Botany, Stockholm University, 106 91 Stockholm, Sweden Kristoffer Hylander, Department of Botany, Stockholm University, 106 91 Stockholm, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Termites are a highly uncertain component in the global source budgets of CH 4 and CO 2 . Large seasonal variations in termite mound fluxes of CH 4 and CO 2 have been reported in tropical savannas but the reason for this is largely unknown. This paper investigated the processes that govern these seasonal variations in CH 4 and CO 2 fluxes from the mounds of Microcerotermes nervosus Hill (Termitidae), a common termite species in Australian tropical savannas. Fluxes of CH 4 and CO 2 of termite mounds were 3.5-fold greater in the wet season as compared to the dry season and were a direct function of termite biomass. Termite biomass in mound samples was tenfold greater in the wet season compared to the dry season. When expressed per unit termite biomass, termite fluxes were only 1.2 (CH 4 ) and 1.4 (CO 2 )-fold greater in the wet season as compared to the dry season and could not explain the large seasonal variations in mound fluxes of CH 4 and CO 2 . Seasonal variation in both gas diffusivity through mound walls and CH 4 oxidation by mound material was negligible. These results highlight for the first time that seasonal termite population dynamics are the main driver for the observed seasonal differences in mound fluxes of CH 4 and CO 2 . These findings highlight the need to combine measurements of gas fluxes from termite mounds with detailed studies of termite population dynamics to reduce the uncertainty in quantifying seasonal variations in termite mound fluxes of CH 4 and CO 2 . Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1991-3 Authors Hizbullah Jamali, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Stephen J. Livesley, Department of Resource Management and Geography, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Tracy Z. Dawes, CSIRO Ecosystem Sciences, PMB 44, Winnellie, NT 0822, Australia Lindsay B. Hutley, Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, NT 0909, Australia Stefan K. Arndt, Department of Forest and Ecosystem Science, The University of Melbourne, 500 Yarra Boulevard, Richmond, VIC 3121, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Although the effects of climate change on biodiversity are increasingly evident by the shifts in species ranges across taxonomical groups, the underlying mechanisms affecting individual species are still poorly understood. The power of climate envelopes to predict future ranges has been seriously questioned in recent studies. Amongst others, an improved understanding of the effects of current weather on population trends is required. We analysed the relation between butterfly abundance and the weather experienced during the life cycle for successive years using data collected within the framework of the Dutch Butterfly Monitoring Scheme for 40 species over a 15-year period and corresponding climate data. Both average and extreme temperature and precipitation events were identified, and multiple regression was applied to explain annual changes in population indices. Significant weather effects were obtained for 39 species, with the most frequent effects associated with temperature. However, positive density-dependence suggested climatic independent trends in at least 12 species. Validation of the short-term predictions revealed a good potential for climate-based predictions of population trends in 20 species. Nevertheless, data from the warm and dry year of 2003 indicate that negative effects of climatic extremes are generally underestimated for habitat specialists in drought-susceptible habitats, whereas generalists remain unaffected. Further climatic warming is expected to influence the trends of 13 species, leading to an improvement for nine species, but a continued decline in the majority of species. Expectations from climate envelope models overestimate the positive effects of climate change in northwestern Europe. Our results underline the challenge to include population trends in predicting range shifts in response to climate change. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2007-z Authors Michiel F. WallisDeVries, De Vlinderstichting/Dutch Butterfly Conservation, P.O. Box 506, 6700 AM Wageningen, The Netherlands Wendy Baxter, De Vlinderstichting/Dutch Butterfly Conservation, P.O. Box 506, 6700 AM Wageningen, The Netherlands Arnold J. H. Van Vliet, Environmental Systems Analysis Group, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    There is considerable theoretical evidence that a trade-off between competitive and colonization ability enables species coexistence. However, empirical studies testing for the presence of a competition–colonization (CC) trade-off and its importance for species coexistence have found mixed results. In a microcosm experiment, we looked for a CC trade-off in a community of six benthic ciliate species. For each species, we measured the time needed to actively disperse to and colonize an empty microcosm. By measuring dispersal rates and growth rates of the species, we were able to differentiate between these two important components of colonization ability. Competitive ability was investigated by comparing species’ growth with or without a competitor in all pairwise species combinations. Species significantly differed in their colonization abilities, with good colonizers having either high growth rates or high dispersal rates or both. Although species showed a clear competitive hierarchy, competitive and colonization ability were uncorrelated. The weakest competitors were also the weakest colonizers, and the strongest competitor was an intermediate colonizer. However, some of the inferior competitors had higher colonization abilities than the strongest competitor, indicating that a CC trade-off may enable coexistence for a subset of the species. Absence of a community-wide CC trade-off may be based on the lack of strong relationships between the traits underlying competitive and colonization ability. We show that temporal effects and differential resource use are alternative mechanisms of coexistence for the species that were both slow colonizers and poor competitors. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-2013-1 Authors Romana Limberger, Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria Stephen A. Wickham, Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Bodies of water are a key foraging habitat for insectivorous bats. Since water is a scarce and limiting resource in arid environments, bodies of open water may have a structuring effect on desert bat communities, resulting in temporal or spatial partitioning of bat activity. Using acoustic monitoring, we studied the spatial and temporal activity patterns of insectivorous bats over desert ponds, and hypothesised that sympatric bat species partition the foraging space above ponds based on interspecific competitive interactions. We used indirect measures of competition (niche overlap and competition coefficients from the regression method) and tested for differences in pond habitat selection and peak activity time over ponds. We examined the effect of changes in the activity of bat species on their potential competitors. We found that interspecific competition affects bat community structure and activity patterns. Competing species partitioned their use of ponds spatially, whereby each species was associated with different pond size and hydroperiod (the number of months a pond holds water) categories, as well as temporally, whereby their activity peaked at different hours of the night. The drying out of temporary ponds increased temporal partitioning over permanent ponds. Differences in the activity of species over ponds in response to the presence or absence of their competitors lend further support to the role of interspecific competition in structuring desert bat communities. We suggest that habitat use and night activity pattern of insectivorous bats in arid environments reflect the trade-offs between selection of preferred pond type or activity time and constraints posed by competitive interactions. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1995-z Authors Orly Razgour, Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990 Midreshet Ben-Gurion, Israel Carmi Korine, Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990 Midreshet Ben-Gurion, Israel David Saltz, Mitrani Department of Desert Ecology, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, 84990 Midreshet Ben-Gurion, Israel Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Decomposer fungi are primary decomposing agents in terrestrial soils. Their mycelial networks play an important role in nutrient mineralisation and distribution, but are also nutritious resources for various soil invertebrates. Global climate change is predicted to alter the diversity and community composition of these soil fauna. To understand whether changes in invertebrate species diversity are likely to affect fungal-mediated decomposition, this study compared the grazing potentials of different invertebrate taxa and functional groups. Specifically, the grazing impacts of seven invertebrate taxa on the growth and spatial distribution of six basidiomycete fungi growing from beech wood blocks in soil microcosms were explored. Wood decay rates by fungi were also compared. The consequences of grazing were both taxon- and species-specific. Generally, macro-invertebrates caused the greatest damage, while meso- and micro-invertebrates often stimulated mycelial growth. Invertebrate size, preferences and population dynamics are likely to influence grazing potentials. Effects of grazing varied between fungi, with mycelial morphology and biochemistry possibly influencing susceptibility. Heavy grazing indirectly increased fungal-mediated wood decomposition. Changes in invertebrate community composition are predicted to have consequences for fungal growth, activity and community structure in woodland soils. Abiotic climate change factors including CO 2 and temperature affect mycelial productivity directly, but the indirect effects, mediated through changes in the soil invertebrate community, may be equally important in controlling ecosystem functioning. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2005-1 Authors Thomas W. Crowther, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK Lynne Boddy, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK T. Hefin Jones, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Carbon (C) allocation and turnover in arctic bryophytes is largely unknown, but their response to climatic change has potentially significant impacts on arctic ecosystem C budgets. Using a combination of pulse-chase experiments and a newly developed model of C turnover in bryophytes, we show significant differences in C turnover between two contrasting arctic moss species ( Polytrichum piliferum and Sphagnum fuscum ). 13 C abundance in moss tissues (measured up to 1 year) and respired CO 2 (traced over 5 days) were used to parameterise the bryophyte C model with four pools representing labile and structural C in photosynthetic and stem tissue. The model was optimised using an Ensemble Kalman Filter to ensure a focus on estimating the confidence intervals (CI) on model parameters and outputs. The ratio of aboveground NPP:GPP in Polytrichum piliferum was 23% (CI 9–35%), with an average turnover time of 1.7 days (CI 1.1–2.5 days). The aboveground NPP:GPP ratio in Sphagnum fuscum was 43% (CI 19–65%) with an average turnover time of 3.1 days (CI 1.6–6.1 days). These results are the first to show differences in C partitioning between arctic bryophyte species in situ and highlight the importance of modelling C dynamics of this group separately from vascular plants for a realistic representation of vegetation in arctic C models. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-1988-y Authors L. E. Street, School of Geosciences, Crew Building, University of Edinburgh, Edinburgh, EH9 3JN UK J. A. Subke, Stockholm Environment Institute York, Environment Department, University of York, York, YO10 5DD UK M. Sommerkorn, Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH UK A. Heinemeyer, Stockholm Environment Institute York, Environment Department, University of York, York, YO10 5DD UK M. Williams, School of Geosciences, Crew Building, University of Edinburgh, Edinburgh, EH9 3JN UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Exotic plants are generally considered a serious problem in wildlands around the globe. However, some argue that the impacts of exotic plants have been exaggerated and that biodiversity and other important plant community characteristics are commonly improved with invasion. Thus, disagreement exists among ecologists as to the relationship of exotic plants with biodiversity and native plant communities. A better understanding of the relationships between exotic plants and native plant communities is needed to improve funding allocation and legislation regarding exotic plants, and justify and prioritize invasion management. To evaluate these relationships, 65 shrub–bunchgrass plant communities with varying densities of an exotic annual grass, Taeniatherum caput - medusae (L.) Nevski (medusahead), were sampled across 160,000 ha in southeastern Oregon, United States. Environmental factors were generally not correlated with plant community characteristics when exotic annual grass density was included in models. Plant diversity and species richness were negatively correlated with exotic annual grass density. Exotic annual grass density explained 62% of the variation in plant diversity. All native plant functional groups, except annual forbs, exhibited a negative relationship with T. caput - medusae . The results of this study suggest that T. caput - medusae invasions probably have substantial negative impacts on biodiversity and native plant communities. The strength of the relationships between plant community characteristics and T. caput - medusae density suggests that some exotic plants are a major force of change in plant communities and subsequently threaten ecosystem functions and processes. However, experimental studies are needed to fully substantiate that annual grass invasion is the cause of these observed correlations. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1992-2 Authors Kirk W. Davies, United States Department of Agriculture, Agricultural Research Service, Eastern Oregon Agricultural Research Center, 67826-A Hwy 205, Burns, OR 97720, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Moisture inputs drive soil respiration (SR) dynamics in semi-arid and arid ecosystems. However, determining the contributions of root and microbial respiration to SR, and their separate temporal responses to periodic drought and water pulses, remains poorly understood. This study was conducted in a pine forest ecosystem with a Mediterranean-type climate that receives seasonally varying precipitation inputs from both rainfall (in the winter) and fog-drip (primarily in the summer). We used automated SR measurements, radiocarbon SR source partitioning, and a water addition experiment to understand how SR, and its separate root and microbial sources, respond to seasonal and episodic changes in moisture. Seasonal changes in SR were driven by surface soil water content and large changes in root respiration contributions. Superimposed on these seasonal patterns were episodic pulses of precipitation that determined the short-term SR patterns. Warm season precipitation pulses derived from fog-drip, and rainfall following extended dry periods, stimulated the largest SR responses. Microbial respiration dominated these SR responses, increasing within hours, whereas root respiration responded more slowly over days. We conclude that root and microbial respiration sources respond differently in timing and magnitude to both seasonal and episodic moisture inputs. These findings have important implications for the mechanistic representation of SR in models and the response of dry ecosystems to changes in precipitation patterns. Content Type Journal Article Pages 1-14 DOI 10.1007/s00442-011-1975-3 Authors Mariah S. Carbone, Department of Geography, University of California, Santa Barbara, CA 93106-4060, USA Christopher J. Still, Department of Geography, University of California, Santa Barbara, CA 93106-4060, USA Anthony R. Ambrose, Department of Integrative Biology, University of California, Berkeley, CA 94720, USA Todd E. Dawson, Department of Integrative Biology, University of California, Berkeley, CA 94720, USA A. Park Williams, Department of Geography, University of California, Santa Barbara, CA 93106-4060, USA Claudia M. Boot, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA Sean M. Schaeffer, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA Joshua P. Schimel, Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, CA 93106, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Demographic rates of migratory species passing through several areas during their annual cycle may be affected by environmental conditions at each of these areas. Recent studies provide evidence that their impact is not necessarily immediate, but can be delayed. We studied survival, reproductive success and arrival date at the breeding grounds of red-backed shrikes Lanius collurio , a trans-Saharan migrant, in relation to weather and vegetation on the breeding grounds, the stopover sites during migration and in the wintering areas. These environmental factors are used as proxy of the shrike’s food supply. We analysed detailed demographic data of some 4,600 individuals from 25 years with multistate capture–recapture and mixed models. Survival probabilities of juveniles and breeders of both sexes varied in parallel across time, suggesting that all cohorts were sensitive to similar causes of mortality. Reproductive performance increased with temperature and decreased with rainfall on the breeding area. Moreover, it increased with vegetation cover in the Sahelian stopover area used on autumn migration suggesting a carry-over effect. Arrival date was negatively affected by spring temperatures in the breeding area. Hence, demographic rates were affected by environmental factors on the breeding grounds, but also outside and elsewhere. This suggests that the shrike’s population dynamics are driven by environmental factors operating at various scales of space and time. However, only a small amount of the temporal variation in demographic rates is explained by the environmental factors considered, suggesting that additional factors, such as those operating during migration, might be important. Content Type Journal Article Pages 1-15 DOI 10.1007/s00442-011-1999-8 Authors Michael Schaub, Swiss Ornithological Institute, 6204 Sempach, Switzerland Hans Jakober, Friedrichstrasse 8/1, 73329 Kuchen, Germany Wolfgang Stauber, Bismarckstrasse 6, 73333 Gingen/Fils, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Much recent ecological research has centred on the interrelations between species diversity and ecological processes. In the present study, I show how species traits may aid in comprehending ecology by studying the link between an environmental variable and functional traits. I examined the composition of species traits with a theoretically underpinned relationship to ecological processes along a pH gradient. I focused on body size, reproductive output, life cycle length and feeding habit of mayflies and stoneflies. In mayfly assemblages, I found smaller body size, greater reproductive output, faster life cycles and a larger proportion of gathering collectors and scrapers with increasing pH. In stonefly assemblages, I found smaller body size, greater reproductive output and faster life cycles at sites with a history of long-term natural acidification, but no clear trends in feeding habits and in most traits where acidification is anthropogenic. The results suggest that mayflies and stoneflies exhibit different ecological functions following different ecological strategies. Mayflies follow an opportunistic strategy relative to stoneflies, likely facilitating high rates of ecological processes with respect to the autotrophic resource base at neutral sites. Relative to mayflies, stoneflies follow an equilibrium strategy contributing to ecological functioning in heterotrophic ecosystems and likely maintaining heterotrophic processes despite the erosion of species diversity in response to acidification. The rules governing an ecological community may be more readily revealed by studying the distribution of species traits instead of species diversity; by studying traits, we are likely to improve our understanding of the workings of ecological communities. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2003-3 Authors Zlatko Petrin, Norwegian Institute for Nature Research (NINA), Postbox 5685, Sluppen, 7485 Trondheim, Norway Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Repeated, spatially explicit sampling is widely used to characterize the dynamics of sessile communities in both terrestrial and aquatic systems, yet our understanding of the consequences of errors made in such sampling is limited. In particular, when Markov transition probabilities are calculated by tracking individual points over time, misidentification of the same spatial locations will result in biased estimates of transition probabilities, successional rates, and community trajectories. Nonetheless, to date, all published studies that use such data have implicitly assumed that resampling occurs without error when making estimates of transition rates. Here, we develop and test a straightforward maximum likelihood approach, based on simple field estimates of resampling errors, to arrive at corrected estimates of transition rates between species in a rocky intertidal community. We compare community Markov models based on raw and corrected transition estimates using data from Endocladia muricata -dominated plots in a California intertidal assemblage, finding that uncorrected predictions of succession consistently overestimate recovery time. We tested the precision and accuracy of the approach using simulated datasets and found good performance of our estimation method over a range of realistic sample sizes and error rates. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1979-z Authors Letitia L. Conway-Cranos, Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, 95060 USA Daniel F. Doak, Department of Zoology and Physiology, University of Wyoming, Laramie, 82071 USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    In networks of plant–animal mutualisms, different animal groups interact preferentially with different plants, thus forming distinct modules responsible for different parts of the service. However, what we currently know about seed dispersal networks is based only on birds. Therefore, we wished to fill this gap by studying bat–fruit networks and testing how they differ from bird–fruit networks. As dietary overlap of Neotropical bats and birds is low, they should form distinct mutualistic modules within local networks. Furthermore, since frugivory evolved only once among Neotropical bats, but several times independently among Neotropical birds, greater dietary overlap is expected among bats, and thus connectance and nestedness should be higher in bat–fruit networks. If bat–fruit networks have higher nestedness and connectance, they should be more robust to extinctions. We analyzed 1 mixed network of both bats and birds and 20 networks that consisted exclusively of either bats (11) or birds (9). As expected, the structure of the mixed network was both modular ( M  = 0.45) and nested (NODF = 0.31); one module contained only birds and two only bats. In 20 datasets with only one disperser group, bat–fruit networks (NODF = 0.53 ± 0.09, C  = 0.30 ± 0.11) were more nested and had a higher connectance than bird–fruit networks (NODF = 0.42 ± 0.07, C  = 0.22 ± 0.09). Unexpectedly, robustness to extinction of animal species was higher in bird–fruit networks ( R  = 0.60 ± 0.13) than in bat–fruit networks ( R  = 0.54 ± 0.09), and differences were explained mainly by species richness. These findings suggest that a modular structure also occurs in seed dispersal networks, similar to pollination networks. The higher nestedness and connectance observed in bat–fruit networks compared with bird–fruit networks may be explained by the monophyletic evolution of frugivory in Neotropical bats, among which the diets of specialists seem to have evolved from the pool of fruits consumed by generalists. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1984-2 Authors Marco Aurelio Ribeiro Mello, Institut für Experimentelle Ökologie, Universität Ulm, Biologie 3, Albert-Einstein-Allee 11, 89069 Ulm, Germany Flávia Maria Darcie Marquitti, Programa de Pós-graduação em Ecologia, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz s/n, Campinas, SP 13083-970, Brazil Paulo R. Guimarães, Departamento de Ecologia, Universidade de São Paulo, Rua do Matão, Trav. 14, n. 321, São Paulo, SP 05508-900, Brazil Elisabeth Klara Viktoria Kalko, Institut für Experimentelle Ökologie, Universität Ulm, Biologie 3, Albert-Einstein-Allee 11, 89069 Ulm, Germany Pedro Jordano, Integrative Ecology Group, Estación Biológica de Doñana, CSIC, Apartado 1056, 41080 Sevilla, Spain Marcus Aloizio Martinez de Aguiar, Instituto de Física ‘Gleb Wataghin’, Universidade Estadual de Campinas, Campinas, SP 13083-970, Brazil Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Environmental conditions and plant genotype may influence insect herbivory along elevational gradients. Plant damage would decrease with elevation as temperature declines to suboptimal levels for insects. However, host plants at higher elevations may exhibit traits that either reduce or enhance leaf quality to insects, with uncertain net effects on herbivory. We examined folivory, insect abundance and leaf traits along six replicated elevational ranges in Nothofagus pumilio forests of the northern Patagonian Andes, Argentina. We also conducted a reciprocal transplant experiment between low- and high-elevation sites to test the extent of environmental and plant genetic control on insect abundance and folivory. We found that insect abundance, leaf size and specific leaf area decreased, whereas foliar phosphorous content increased, from low-, through mid- to high-elevation sites. Path analysis indicated that changes in both insect abundance and leaf traits were important in reducing folivory with increasing elevation and decreasing mean temperature. At both planting sites, plants from a low-elevation origin experienced higher damage and supported greater insect loads than plants from a high-elevation origin. The differences in leaf damage between sites were twofold larger than those between plant origins, suggesting that local environment was more important than host genotype in explaining folivory patterns. Different folivore guilds exhibited qualitatively similar responses to elevation. Our results suggest an increase in insect folivory on high-elevation N. pumilio forests under future climate warming scenarios. However, in the short-term, folivory increases might be smaller than expected from insect abundance only because at high elevations herbivores would encounter more resistant tree genotypes. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-1978-0 Authors Lucas A. Garibaldi, Laboratorio Ecotono, INIBIOMA-CONICET and CRUB-UNCOMA, Quintral 1250, CP8400 S. C. de Bariloche, Río Negro, Argentina Thomas Kitzberger, Laboratorio Ecotono, INIBIOMA-CONICET and CRUB-UNCOMA, Quintral 1250, CP8400 S. C. de Bariloche, Río Negro, Argentina Enrique J. Chaneton, IFEVA-CONICET, Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín 4453, C1417DSE Ciudad Autónoma de Buenos Aires, Argentina Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Age and size at maturation are important correlates of fitness in many organisms and understanding how these are influenced by environmental conditions is therefore required to predict populations’ responses to environmental changes. In ectotherms, growth and maturation are closely linked to temperature, but nonetheless it is often unclear how temperature-induced variation in growth and temperature per se translate to the process of maturation. Here, we test this explicitly with a common garden experiment using nine-spined sticklebacks ( Pungitius pungitius ). We reared fish in 14 and 17°C and recorded high resolution growth trajectories and the timing of maturation on an individual basis. To characterize the growth of each individual, we fitted a von Bertalanffy growth curve to each measured growth trajectory, so that the three parameters of the curve provided a summary of an individual’s growth. Temperature treatments induced changes in both the growth parameters and the age at maturation. In females, changes in the age of maturation were encompassed by variations in growth, whereas in males there was a temperature-related shift in the age at maturation that was unrelated to growth. Our experiment demonstrates that temperature can affect maturation directly, and not only through temperature-induced changes in growth. Therefore, one cannot predict, on the basis of growth only, how changes in temperature might alter age and size at maturation and the subsequent reproduction. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1989-x Authors Anna Kuparinen, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland José M. Cano, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland John Loehr, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Gábor Herczeg, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Abigel Gonda, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Juha Merilä, Ecological Genetics Research Unit, Department of Biosciences, University of Helsinki, P.O. Box 65, 00014 Helsinki, Finland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Fires shape fundamental properties of many forest ecosystems and climate change will increase their relevance in regions where fires occur infrequently today. In ecosystems that are not adapted to fire, post-fire tree recruitment is often sparse, a fact that might be attributed to a transient lack of mycorrhizae. Ectomycorrhizal (EcM) fungi play an important role for recruitment by enhancing nutrient and water uptake of their hosts. The questions arise whether and for how long the EcM community is transformed by fire. We investigated the resistance and resilience of EcM fungal communities on a chronosequence of 12 Pinus sylvestris stands in Valais (Switzerland) and Val d’Aosta (Italy) affected by fire between 1990 and 2006. Soil samples from burnt and non-burnt forests were analyzed with respect to EcM fungi by means of a bioassay. The number of EcM species was significantly lower in samples from recently (2–5 years) burnt sites than non-burnt forest, and increased with time since fire reaching levels of adjacent forests after 15–18 years. Community composition changed after fire but did not converge to that of non-burnt sites over the 18 year period. Only Rhizopogon roseolus and Cenococcum geophilum were abundant in both burnt sites and adjacent forest. Our data indicate fire resistance of some EcM fungal species as well as rapid resilience in terms of species number, but not in species composition. As long as the function of different EcM species for seedling establishment is unknown, the consequences of long-term shifts in EcM community composition for tree recruitment remain unclear. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1981-5 Authors Tabea Kipfer, Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Barbara Moser, Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Simon Egli, Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Thomas Wohlgemuth, Swiss Federal Research Institute WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Jaboury Ghazoul, Institute of Terrestrial Ecosystems, ETH Zürich, Universitätsstrasse 16, 8092 Zürich, Switzerland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plants flowering together may influence each other’s pollination and fecundity over a range of physical distances. Their effects on one another can be competitive, neutral, or facilitative. We manipulated the floral neighborhood of the high-alpine cushion plant Eritrichium nanum in the Swiss Alps and measured the effects of co-flowering neighbors on both the number of seeds produced and the degree of inbreeding and outbreeding in the offspring, as deduced from nuclear microsatellite markers. Seed set of E. nanum did not vary significantly with the presence or absence of two Saxifraga species growing as near neighbors, but it was higher in E. nanum cushions growing at low conspecific density than in those growing at high density. In addition, floral neighborhood had no detectable effect on the degree of selfing of E. nanum , but seeds from cushions growing at low conspecific density were more highly outbred than seeds from cushions at high density. Thus, there was no evidence of either competition or facilitation between E. nanum and Saxifraga spp. as mediated by pollinators at the spatial scale of our experimental manipulation. In contrast, the greater fecundity of E. nanum cushions at low density was consistent with reduced intraspecific competition for pollinators and might also represent a beneficial effect of highly outbred seeds as brought about by more long-distance pollinator flights under low-density conditions. Content Type Journal Article Pages 1-8 DOI 10.1007/s00442-011-1985-1 Authors Lea R. Wirth, WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Nickolas M. Waser, School of Natural Resources and the Environment, University of Arizona, Tucson, AZ 85721, USA René Graf, WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Felix Gugerli, WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Urs Landergott, WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Andreas Erhardt, Integrative Biology, University of Basel, St. Johanns-Vorstadt 10, 4056 Basel, Switzerland Hans Peter Linder, Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland Rolf Holderegger, WSL Swiss Federal Research Institute, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The adaptive fitness of a freeze-tolerant insect may be mediated by both endogenous and exogenous interactions. The aim of the study presented here was to characterize the freeze tolerance of alpine Tiger moth caterpillars ( Metacrias huttoni ) and highlight two poorly explored indices of the potential attrition of fitness: (1) downstream development and reproduction; (2) parasitism. Caterpillars survived temperatures as low as −16°C and demonstrated 〉90% 72-h survival after exposures to −10°C. Two-week acclimations at 5, 10, and 20°C had no effect on body water content, haemolymph osmolality or survival of equilibrium freezing, but there was a significant elevation of the temperature of crystallization ( T c ) in those caterpillars acclimated to 5°C. Cell viability of fat body tissue was resilient to freezing (−10 to −16°C), but midgut and tracheal cells showed significant degradation. Pupation and eclosion were unaffected by freezing at −5 or −10°C. Likewise, there were no significant differences in egg production or the proportion of eggs that hatched between control and frozen insects. By contrast, the ability of tachinid larvae to survive freezing within their hosts means that parasitism plays an important role in regulating population size. Mean parasitism of caterpillars by tachinids was 33.3 ± 7.2%. Pupation and imago emergence of tachinids after host ‘endo-nucleation’ was 〉75%. Eclosed adult tachinids showed a non-significant increase in the incidence of wing abnormalities in relation to low temperature exposure. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1983-3 Authors T. C. Hawes, Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand D. A. Wharton, Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Pollinators, even floral generalists (=polyleges), typically specialize during individual foraging bouts, infrequently switching between floral hosts. Such transient floral constancy restricts pollen flow, and thereby gene flow, to conspecific flowers in mixed plant communities. Where incipient flowering species meet, however, weak cross-fertility and often similar floral traits can yield mixed reproductive outcomes among pollinator-dependent species. In these cases, floral constancy by polyleges sometimes serves as an ethological mating barrier. More often, their foraging infidelities instead facilitate host introgression and hybridization. Many other bee species are oligolectic (taxonomic specialists for pollen). Oligoleges could be more discriminating connoisseurs than polyleges when foraging among their limited set of related floral hosts. If true, greater foraging constancy might ensue, contributing to positive assortative mating and disruptive selection, thereby facilitating speciation among their interfertile floral hosts. To test this Connoisseur Hypothesis, nesting females of two species of oligolectic Osmia bees were presented with randomized mixed arrays of flowers of two sympatric species of their pollen host, Balsamorhiza , a genus known for hybridization. In a closely spaced grid, the females of both species preferred the larger flowered B. macrophylla , evidence for discrimination. However, both species’ females showed no floral constancy whatsoever during their individual foraging bouts, switching randomly between species proportional to their floral preference. In a wider spaced array in which the bouquets reflected natural plant spacing, foraging oligolectic bees often transferred pollen surrogates (fluorescent powders) both between conspecific flowers (geitonogamy and xenogamy) and between the two Balsamorhiza species. The Connoisseur Hypothesis was therefore rejected. Foraging infidelity by these oligolectic Osmia bees will contribute to introgression and hybridization where interfertile species of Balsamorhiza meet and flower together. A literature review reveals that other plant genera whose species hybridize also attract numerous oligolectic bees, providing independent opportunities to test the generality of this conclusion. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1977-1 Authors James H. Cane, USDA Bee Biology and Systematics Lab, Utah State University, Logan, UT 84322-5310, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The inverse relationship between the number of stomata on a leaf surface and the atmospheric carbon dioxide concentration ([CO 2 ]) in which the leaf developed allows plants to optimise water-use efficiency (WUE), but it also permits the use of fossil plants as proxies of palaeoatmospheric [CO 2 ]. The ancient conifer family Araucariaceae is often represented in fossil floras and may act as a suitable proxy of palaeo-[CO 2 ], yet little is known regarding the stomatal index (SI) responses of extant Araucariaceae to [CO 2 ]. Four Araucaria species ( Araucaria columnaris , A. heterophylla , A. angustifolia and A. bidwillii ) and Agathis australis displayed no significant relationship in SI to [CO 2 ] below current ambient levels (~380 ppm). However, representatives of the three extant genera within the Araucariaceae ( A. bidwillii , A. australis and Wollemia nobilis ) all exhibited significant reductions in SI when grown in atmospheres of elevated [CO 2 ] (1,500 ppm). Stomatal conductance was reduced and WUE increased when grown under elevated [CO 2 ]. Stomatal pore length did not increase alongside reduced stomatal density (SD) and SI in the three araucariacean conifers when grown at elevated [CO 2 ]. These pronounced SD and SI reductions occur at higher [CO 2 ] levels than in other species with more recent evolutionary origins, and may reflect an evolutionary legacy of the Araucariaceae in the high [CO 2 ] world of the Mesozoic Era. Araucariacean conifers may therefore be suitable stomatal proxies of palaeo-[CO 2 ] during periods of “greenhouse” climates and high [CO 2 ] in the Earth’s history. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1969-1 Authors Matthew Haworth, CNR-Istituto di Biometeorologia (IBIMET), Via Giovanni Caproni 8, 50145 Firenze, Italy Caroline Elliott-Kingston, School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland Jennifer C. McElwain, School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    One major characteristic of invasive alien species is their occurrence at high abundances in their new habitat. Flowering invasive plant species that are visited by native insects and overlap with native plant species in their pollinators may facilitate or disrupt native flower visitation and fertilisation by forming large, dense populations with high numbers of flowers and copious rewards. We investigated the direction of such a proposed effect for the alien invasive Rhododendron ponticum in Irish habitats. Flower visitation, conspecific and alien pollen deposition, fruit and seed set were measured in a self-compatible native focal plant, Digitalis purpurea , and compared between field sites that contained different relative abundances of R. ponticum . Flower visitation was significantly lower at higher alien relative plant abundances than at lower abundances or in the absence of the alien. Native flowers experienced a significant decrease in conspecific pollen deposition with increasing alien abundance. Heterospecific pollen transfer was very low in all field sites but increased significantly with increasing relative R. ponticum abundance. However, lower flower visitation and lower conspecific pollen transfer did not alter reproductive success of D. purpurea . Our study shows that indirect interactions between alien and native plants for pollination can be modified by population characteristics (such as relative abundance) in a similar way as interactions among native plant species. In D. purpurea , only certain aspects of pollination and reproduction were affected by high alien abundances which is probably a result of high resilience due to a self-compatible breeding system. Native species that are more susceptible to pollen limitation are more likely to experience fitness disadvantages in habitats with high relative alien plant abundances. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1987-z Authors Anke Christiane Dietzsch, School of Natural Sciences, Botany Building, Trinity College, Dublin 2, Ireland Dara Anne Stanley, School of Natural Sciences, Botany Building, Trinity College, Dublin 2, Ireland Jane Catherine Stout, School of Natural Sciences, Botany Building, Trinity College, Dublin 2, Ireland Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Understanding how communities assemble is a key challenge in ecology. Conflicting hypotheses suggest that plant traits within communities should show divergence to reflect strategies to reduce competition or convergence to reflect strong selection for the environmental conditions operating. Further hypotheses suggest that plant traits related to productivity show convergence within communities, but those related to disturbance show divergence. Data on functional diversity (FD var ) of 12 traits from 30 communities ranging from arable fields, mown and grazed grasslands to moorland and woodland were employed to test this using randomisations tests and correlation and regression analysis. No traits showed consistent significant convergence or divergence in functional diversity. When correlated to measures of the environment, the most common pattern was for functional diversity to decline (7 out of 12 traits) and the degree of convergence (7 out of 12 traits) to increase as the levels of productivity (measured as primary productivity, soil nitrogen release and vegetation C:N) and disturbance increased. Convergence or a relationship between functional diversity and the environment was not seen for a number of important traits, such as LDMC and SLA, which are considered as key predictors of ecosystem function. The analysis indicates that taking into account functional diversity within a system may be a necessary part of predicting the relationship between plant traits and ecosystem function, and that this may be of particular importance within less productive and less disturbed systems. Content Type Journal Article Pages 1-10 DOI 10.1007/s00442-011-1980-6 Authors Robin J. Pakeman, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH UK Jack J. Lennon, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH UK Rob W. Brooker, The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Variation in habitat quality can have important consequences for fitness and population dynamics. For food-caching species, a critical determinant of habitat quality is normally the density of storable food, but it is also possible that quality is driven by the ability of habitats to preserve food items. The food-caching gray jay ( Perisoreus canadensis ) occupies year-round territories in the coniferous boreal and subalpine forests of North America, but does not use conifer seed crops as a source of food. Over the last 33 years, we found that the occupancy rate of territories in Algonquin Park (ON, Canada) has declined at a higher rate in territories with a lower proportion of conifers compared to those with a higher proportion. Individuals occupying territories with a low proportion of conifers were also less likely to successfully fledge young. Using chambers to simulate food caches, we conducted an experiment to examine the hypothesis that coniferous trees are better able to preserve the perishable food items stored in summer and fall than deciduous trees due to their antibacterial and antifungal properties. Over a 1–4 month exposure period, we found that mealworms, blueberries, and raisins all lost less weight when stored on spruce and pine trees compared to deciduous and other coniferous trees. Our results indicate a novel mechanism to explain how habitat quality may influence the fitness and population dynamics of food-caching animals, and has important implications for understanding range limits for boreal breeding animals. Content Type Journal Article Pages 1-8 DOI 10.1007/s00442-011-2040-y Authors Dan Strickland, 1063 Oxtongue Lake Road, Dwight, ON P0A 1H0, Canada Brian Kielstra, Department of Geography, University of Guelph, Guelph, ON N1G 2W1, Canada D. Ryan Norris, Department of Integrative Biology, University of Guelph, Guelph, ON N1G 2W1, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The enormous success of the genus Daphnia in freshwater ecosystems is at least partially due to their cyclical parthenogenetic life cycle, in which asexual and sexual reproduction alternate periodically. This temporal change between reproductive strategies allows for (1) rapid population growth via subitaneously developing eggs when environmental conditions are appropriate and (2) the maintenance of genetic diversity via sexual reproduction and the production of resting eggs when environmental conditions deteriorate. We show here that dietary amino acids are involved in triggering the switch between reproductive modes in Daphnia pulex . Supplementation experiments demonstrate that specific dietary amino acids, in particular arginine and histidine, avert crowding-induced resting egg production, enhance subitaneous reproduction by increasing algal food quality and, as a combined effect of both processes, increase population growth rates. These findings suggest that the availability of single dietary amino acids potentially affects the seasonal dynamics and long-term persistence of Daphnia populations in the field, which may have consequences for the efficiency of carbon transfer and thus the trophic structure of freshwater food webs. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2047-4 Authors Ulrike Koch, Limnological Institute, University of Konstanz, Mainaustrasse 252, 78464 Constance, Germany Dominik Martin-Creuzburg, Limnological Institute, University of Konstanz, Mainaustrasse 252, 78464 Constance, Germany Hans-Peter Grossart, Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin, Limnology of Stratified Lakes, Alte Fischerhütte 2, OT Neuglobsow, 16775 Stechlin, Germany Dietmar Straile, Limnological Institute, University of Konstanz, Mainaustrasse 252, 78464 Constance, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The driving factors of survival, a key demographic process, have been particularly challenging to study, especially for winter migratory species such as the Adélie penguin ( Pygoscelis adeliae ). While winter environmental conditions clearly influence Antarctic seabird survival, it has been unclear to which environmental features they are most likely to respond. Here, we examine the influence of environmental fluctuations, broad climatic conditions and the success of the breeding season prior to winter on annual survival of an Adélie penguin population using mark–recapture models based on penguin tag and resight data over a 16-year period. This analysis required an extension to the basic Cormack–Jolly–Seber model by incorporating age structure in recapture and survival sub-models. By including model covariates, we show that survival of older penguins is primarily related to the amount and concentration of ice present in their winter foraging grounds. In contrast, fledgling and yearling survival depended on other factors in addition to the physical marine environment and outcomes of the previous breeding season, but we were unable to determine what these were. The relationship between sea-ice and survival differed with penguin age: extensive ice during the return journey to breeding colonies was detrimental to survival for the younger penguins, whereas either too little or too much ice (between 15 and 80% cover) in the winter foraging grounds was detrimental for adults. Our results demonstrate that predictions of Adélie penguin survival can be improved by taking into account penguin age, prior breeding conditions and environmental features. Content Type Journal Article Pages 1-15 DOI 10.1007/s00442-011-2044-7 Authors Louise Emmerson, Australian Antarctic Division, Department of Sustainability, Environment, Water, Population and Communities, Channel Highway, Kingston, TAS 7050, Australia Colin Southwell, Australian Antarctic Division, Department of Sustainability, Environment, Water, Population and Communities, Channel Highway, Kingston, TAS 7050, Australia Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Predation and food resources can strongly affect small mammal population dynamics directly by altering vital rates or indirectly by influencing behaviors. Fire may also strongly influence population dynamics of species inhabiting fire-adapted habitats because fire can alter food and cover availability. We used capture–mark–recapture and radio-telemetry studies to experimentally examine how supplemental feeding, mammalian predator exclusion, and prescribed fire affected survival, abundance, and reproduction of hispid cotton rats ( Sigmodon hispidus ) in southwestern Georgia, USA. Prescribed fire reduced survival, abundance, and rates of transitions to reproductive states. Food supplementation increased survival, transitions to reproductive states, and abundance, but was not sufficient to prevent post-fire declines in any of these parameters. Mammalian predator exclusion did not strongly affect any of the considered parameters. Our results show that fire strongly influenced cotton rat populations in our study site, primarily by reducing cover and increasing predation risk from non-mammalian predators. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2053-6 Authors Gail Morris, Joseph W. Jones Ecological Research Center, 3988 Jones Center Dr, Newton, GA 39870, USA Jeffrey A. Hostetler, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA L. Mike Conner, Joseph W. Jones Ecological Research Center, 3988 Jones Center Dr, Newton, GA 39870, USA Madan K. Oli, Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32611, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    A cost of reproduction in terms of reduced future performance underlies all life-history models, yet costs have been difficult to detect in short-term experiments with long-lived plants. The likelihood of detecting costs should depend on the range of variation in reproductive effort that can be induced, and also on the shape of the cost function across this range, which should be affected by resource availability. Here, we experimentally examined the effects of both reduced and increased fruit production in two populations of the long-lived orchid Gymnadenia conopsea located at sites that differ in length of the growing season. Plants that were prevented from fruiting produced more flowers in the population with a longer growing season, had higher survival in the other population, and grew larger compared to control plants in both populations. Fruit production was pollen-limited in both populations, and increased reproductive investment after supplemental hand-pollination was associated with reduced fecundity the following year. The results demonstrate that the shape of the cost function varies among fitness components, and that costs can be differentially expressed in different populations. They are consistent with the hypothesis that differences in temporal overlap between allocation to reproduction and other functions will induce among-population variation in reproductive costs. Content Type Journal Article Pages 1-8 DOI 10.1007/s00442-011-2006-0 Authors Nina Sletvold, NTNU, Museum of Natural History and Archaeology, 7491 Trondheim, Norway Jon Ågren, Plant Ecology and Evolution, Department of Ecology and Genetics, EBC, Uppsala University, Norbyvägen 18 D, 752 36 Uppsala, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Within-range effects of climatic change on tree growth at the sub-regional scale remain poorly understood. The aim of this research was to use climate and radial-growth data to explain how long-term climatic trends affect tree growth patterns along the southern limit of the range of Pinus nigra ssp. salzmannii (Eastern Baetic Range, southern Spain). We used regional temperature and precipitation data and measured sub-regional radial growth variation in P. nigra forests over the past two centuries. A dynamic factor analysis was applied to test the hypothesis that trees subjected to different climates have experienced contrasting long-term growth variability. We defined four representative stand types based on average temperature and precipitation to evaluate climate–growth relationships using linear mixed-effect models and multi-model selection criteria. All four stand types experienced warming and declining precipitation throughout the twentieth century. From the onset of the twentieth century, synchronised basal-area increment decline was accounted for by dynamic factor analysis and was related to drought by climate–growth models; declining basal-area increment trends proved stronger at lower elevations, whereas temperature was positively related to growth in areas with high rainfall inputs. Given the contrasting sub-regional tree-growth responses to climate change, the role of drought becomes even more complex in shaping communities and affecting selection pressure in the Mediterranean mountain forests. Potential vegetation shifts will likely occur over the dry edge of species distributions, with major impacts on ecosystem structure and function. Content Type Journal Article Pages 1-13 DOI 10.1007/s00442-011-2012-2 Authors Juan Carlos Linares, Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera km. 1, 41002 Sevilla, Spain Pedro Antonio Tíscar, Centro de Capacitación y Experimentación Forestal, 23470 Cazorla, Spain Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Optimization theory in combination with canopy modeling is potentially a powerful tool for evaluating the adaptive significance of photosynthesis-related plant traits. Yet its successful application has been hampered by a lack of agreement on the appropriate optimization criterion. Here we review how models based on different types of optimization criteria have been used to analyze traits—particularly N reallocation and leaf area indices—that determine photosynthetic nitrogen-use efficiency at the canopy level. By far the most commonly used approach is static-plant simple optimization (SSO). Static-plant simple optimization makes two assumptions: (1) plant traits are considered to be optimal when they maximize whole-stand daily photosynthesis, ignoring competitive interactions between individuals; (2) it assumes static plants, ignoring canopy dynamics (production and loss of leaves, and the reallocation and uptake of nitrogen) and the respiration of nonphotosynthetic tissue. Recent studies have addressed either the former problem through the application of evolutionary game theory (EGT) or the latter by applying dynamic-plant simple optimization (DSO), and have made considerable progress in our understanding of plant photosynthetic traits. However, we argue that future model studies should focus on combining these two approaches. We also point out that field observations can fit predictions from two models based on very different optimization criteria. In order to enhance our understanding of the adaptive significance of photosynthesis-related plant traits, there is thus an urgent need for experiments that test underlying optimization criteria and competing hypotheses about underlying mechanisms of optimization. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2011-3 Authors Niels P. R. Anten, Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands Heinjo J. During, Ecology and Biodiversity, Institute of Environmental Biology, Utrecht University, P.O. Box 800.84, 3508 TB Utrecht, The Netherlands Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Decomposer fungi are primary decomposing agents in terrestrial soils. Their mycelial networks play an important role in nutrient mineralisation and distribution, but are also nutritious resources for various soil invertebrates. Global climate change is predicted to alter the diversity and community composition of these soil fauna. To understand whether changes in invertebrate species diversity are likely to affect fungal-mediated decomposition, this study compared the grazing potentials of different invertebrate taxa and functional groups. Specifically, the grazing impacts of seven invertebrate taxa on the growth and spatial distribution of six basidiomycete fungi growing from beech wood blocks in soil microcosms were explored. Wood decay rates by fungi were also compared. The consequences of grazing were both taxon- and species-specific. Generally, macro-invertebrates caused the greatest damage, while meso- and micro-invertebrates often stimulated mycelial growth. Invertebrate size, preferences and population dynamics are likely to influence grazing potentials. Effects of grazing varied between fungi, with mycelial morphology and biochemistry possibly influencing susceptibility. Heavy grazing indirectly increased fungal-mediated wood decomposition. Changes in invertebrate community composition are predicted to have consequences for fungal growth, activity and community structure in woodland soils. Abiotic climate change factors including CO 2 and temperature affect mycelial productivity directly, but the indirect effects, mediated through changes in the soil invertebrate community, may be equally important in controlling ecosystem functioning. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-2005-1 Authors Thomas W. Crowther, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK Lynne Boddy, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK T. Hefin Jones, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3AX UK Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Infection-induced changes in a host’s thermal physiology can represent (1) a generalized host response to infection, (2) a pathological side-effect of infection, or (3), provided the parasite’s development is temperature-dependent, a subtle case of host manipulation. This study investigates parasite-induced changes in the thermal biology of a first intermediate host infected by two castrating trematodes (genera Maritrema and Philophthalmus ) using laboratory experiments and field surveys. The heat tolerance and temperatures selected by the snail, Zeacumantus subcarinatus , displayed alterations upon infection that differed between the two trematodes. Upon heating, snails infected by Maritrema sustained activity for longer durations than uninfected snails, followed by a more rapid recovery, and selected higher temperatures in a thermal gradient. These snails were also relatively abundant in high shore localities in the summer only, corresponding with seasonal elevated microhabitat temperatures. By contrast, Philophthalmus -infected snails fell rapidly into a coma upon heating and did not display altered thermal preferences. The respective heat tolerance of each trematode corresponded with the thermal responses induced in the snail: Maritrema survived exposure to 40°C, while Philophthalmus was less heat tolerant. Although both trematodes infect the same tissues, Philophthalmus leads to a reduction in the host’s thermal tolerance, a response consistent with a pathological side effect. By contrast, Maritrema induces heat tolerance in the snail and withstood exposure to high heat. As the developmental rate and infectivity of Maritrema increase with temperature up to 25°C, one adaptive explanation for our findings is that Maritrema manipulates the snail’s thermal responses to exploit warm microhabitats. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-2014-0 Authors A. E. Bates, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand F. Leiterer, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand M. L. Wiedeback, Portobello Marine Laboratory, Department of Marine Science, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand R. Poulin, Zoology Department, University of Otago, P.O. Box 56, Dunedin, 9054 New Zealand Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Food availability is a major environmental factor that can influence life history within and across generations through direct effects on individual quality and indirect effects on the intensity of intra- and intercohort competition. Here, we investigated in yearling and adult common lizards ( Zootoca vivipara ) the immediate and delayed life-history effects of a prolonged food deprivation in the laboratory. We generated groups of fully fed or food-deprived yearlings and adults at the end of one breeding season. These lizards were released in 16 outdoor enclosures together with yearlings and adults from the same food treatment and with food-deprived or fully fed juveniles, creating four types of experimental populations. Experimental populations were then monitored during 2 years, which revealed complex effects of food on life-history trajectories. Food availability had immediate direct effects on morphology and delayed direct effects on immunocompetence and female body condition at winter emergence. Also, male annual survival rate and female growth rate and body size were affected by an interaction between direct effects of food availability and indirect effects on asymmetric competition with juveniles. Reproductive outputs were insensitive to past food availability, suggesting that female common lizards do not solely rely on stored energy to fuel reproduction. Finally, food conditions had socially-mediated intergenerational effects on early growth and survival of offspring through their effects on the intensity of competition. This study highlights the importance of social interactions among cohorts for life-history trajectories and population dynamics in stage-structured populations. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-1933-0 Authors Marianne Mugabo, CNRS, UMR 7625, Laboratoire Ecologie et Evolution, Université Pierre et Marie Curie, 7 Quai St. Bernard, 75005 Paris, France Olivier Marquis, CNRS, UMR 7625, Laboratoire Ecologie et Evolution, Université Pierre et Marie Curie, 7 Quai St. Bernard, 75005 Paris, France Samuel Perret, CNRS/ENS UMS 3194, CEREEP-Ecotron IleDeFrance, École Normale Supérieure, 78 rue du Château, 77140 St-Pierre-lès-Nemours, France Jean-François Le Galliard, CNRS, UMR 7625, Laboratoire Ecologie et Evolution, Université Pierre et Marie Curie, 7 Quai St. Bernard, 75005 Paris, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Future climate change is likely to reduce the floristic diversity of grasslands. Yet the potential consequences of climate-induced plant species losses for the functioning of these ecosystems are poorly understood. We investigated how climate change might alter the functional composition of grasslands for Konza Prairie, a diverse tallgrass prairie in central North America. With species-specific climate envelopes, we show that a reduction in mean annual precipitation would preferentially remove species that are more abundant in the more productive lowland positions at Konza. As such, decreases in precipitation could reduce productivity not only by reducing water availability but by also removing species that inhabit the most productive areas and respond the most to climate variability. In support of this prediction, data on species abundance at Konza over 16 years show that species that are more abundant in lowlands than uplands are preferentially reduced in years with low precipitation. Climate change is likely to also preferentially remove species from particular functional groups and clades. For example, warming is forecast to preferentially remove perennials over annuals as well as Cyperaceae species. Despite these predictions, climate change is unlikely to unilaterally alter the functional composition of the tallgrass prairie flora, as many functional traits such as physiological drought tolerance and maximum photosynthetic rates showed little relationship with climate envelope parameters. In all, although climatic drying would indirectly alter grassland productivity through species loss patterns, the insurance afforded by biodiversity to ecosystem function is likely to be sustained in the face of climate change. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1938-8 Authors Joseph M. Craine, Division of Biology, Kansas State University, Manhattan, KS 66506, USA Jesse B. Nippert, Division of Biology, Kansas State University, Manhattan, KS 66506, USA E. Gene Towne, Division of Biology, Kansas State University, Manhattan, KS 66506, USA Sally Tucker, Division of Biology, Kansas State University, Manhattan, KS 66506, USA Steven W. Kembel, Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, OR 97403, USA Adam Skibbe, Division of Biology, Kansas State University, Manhattan, KS 66506, USA Kendra K. McLauchlan, Department of Geography, Kansas State University, Manhattan, KS 66506, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Reproductive traits are tightly linked to plant fitness and may therefore be mechanisms driving biological invasions, including the greater success of more phylogenetically novel introduced species in some systems. We present a phylogenetic comparative analysis of “Baker’s law’’, that introduced plants with the ability to reproduce autogamous or asexually may be better able to establish on introduction. We gathered data from both published and unpublished sources on pollen limitation of 141 species, including 26 introduced species and 115 native species. Our analysis compared differences in the proportion of autonomous autogamy, asexual reproduction, and pollen limitation among native, introduced noninvasive, and introduced invasive plant species, and included the phylogenetic novelty of the introduced species to the native species in that community. Introduced species were more likely to be autogamous than native species, consistent with Baker’s law. On the other hand, introduced species were less likely to have the ability to reproduce asexually. Further, among species with no autonomous autogamy, pollen limitation was greater for introduced compared to native species. Such a result is consistent with the idea that plants entering a new continent receive lower quality or quantity of services from resident pollinators than species native to that continent. Finally, more phylogenetically novel invasive species had lower pollen limitation than less novel invasive species, potentially because they experience less competition for pollinators. This is the first evidence that enhanced pollination may be one mechanism driving the greater invasiveness of phylogenetically novel introduced species observed in some systems. Content Type Journal Article Pages 1-9 DOI 10.1007/s00442-011-1929-9 Authors Jean H. Burns, Department of Biology, Washington University in St. Louis, St. Louis, MO USA Tia-Lynn Ashman, Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA USA Janette A. Steets, Department of Botany, Oklahoma State University, Stillwater, OK USA Alexandra Harmon-Threatt, Department of Biology, Washington University in St. Louis, St. Louis, MO USA Tiffany M. Knight, Department of Biology, Washington University in St. Louis, St. Louis, MO USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Rapid germination of non-dormant seeds is one adaptation plants have evolved to counter seed predation by rodents. Some rodent species have evolved behaviors that prevent or slow the seed germination process through seed embryo removal or seed pruning; however, no plant species is known to have successfully escaped embryo removal or seed pruning by rodents. Here, we report that the non-dormant seeds of Pittosporopsis kerrii Craib in tropical rain forests in China have a high regeneration capacity to counter seed pruning by rodents. We found seed pruning, instead of embryo removal, was commonly used by rodents to increase food storage time by slowing down the seed germination process, but that P. kerrii seeds have a high regeneration capacity to escape seed predation by rodents: all pruned seeds, pruned roots and embryo-removed seeds by rodents or people retain the ability to develop into seedlings. Seeds of P. kerrii also have other capacities (i.e. rapid seed decomposition and indigestible dormant taproots) to escape predation by reducing the plant’s attractiveness to rodents. The association between seed pruning behavior in rodents and high regeneration capacity of pruned seeds or roots in P. kerrii seeds are likely novel adaptation strategies adopted by seeds and rodents, respectively. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1908-1 Authors Lin Cao, State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China Zhishu Xiao, State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China Zhenyu Wang, State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China Cong Guo, Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, 610064 China Jin Chen, CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303 Yunnan China Zhibin Zhang, State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101 China Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Much recent ecological research has centred on the interrelations between species diversity and ecological processes. In the present study, I show how species traits may aid in comprehending ecology by studying the link between an environmental variable and functional traits. I examined the composition of species traits with a theoretically underpinned relationship to ecological processes along a pH gradient. I focused on body size, reproductive output, life cycle length and feeding habit of mayflies and stoneflies. In mayfly assemblages, I found smaller body size, greater reproductive output, faster life cycles and a larger proportion of gathering collectors and scrapers with increasing pH. In stonefly assemblages, I found smaller body size, greater reproductive output and faster life cycles at sites with a history of long-term natural acidification, but no clear trends in feeding habits and in most traits where acidification is anthropogenic. The results suggest that mayflies and stoneflies exhibit different ecological functions following different ecological strategies. Mayflies follow an opportunistic strategy relative to stoneflies, likely facilitating high rates of ecological processes with respect to the autotrophic resource base at neutral sites. Relative to mayflies, stoneflies follow an equilibrium strategy contributing to ecological functioning in heterotrophic ecosystems and likely maintaining heterotrophic processes despite the erosion of species diversity in response to acidification. The rules governing an ecological community may be more readily revealed by studying the distribution of species traits instead of species diversity; by studying traits, we are likely to improve our understanding of the workings of ecological communities. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2003-3 Authors Zlatko Petrin, Norwegian Institute for Nature Research (NINA), Postbox 5685, Sluppen, 7485 Trondheim, Norway Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Mosses play an integral role in the hydrologic regimes of ecosystems where they cover the soil surface, and thus affect biogeochemical cycling of elements influenced by soil oxidation–reduction (redox) reactions, including the plant growth-limiting nutrients, nitrogen and phosphorus (P). In rich fens where P often limits plant growth, we hypothesized that feedbacks between mosses and redox conditions would determine P availability to shallow-rooted forb species that constitute much of these wetlands’ unusually high plant species diversity. In a moss removal experiment in three fens, forb tissue P and microbial P were greater while anion exchange membrane (AEM) resin P was lower where mosses occurred than where they were removed, suggesting both higher availability and greater demand for P in moss-covered soils. Coupled physicochemical and biological mechanisms drove moss effects on P cycling, ultimately through effects on soil oxygenation or reduction: higher redox potential underlying mosses corresponded to greater microbial activity, phosphatase enzyme activity, and colonization by arbuscular mycorrhizal fungi (AMF), all of which can promote greater P availability to plants. These more oxidized soils stimulated: (1) greater microbial activity and root vigor; (2) correspondingly greater P demand via microbial uptake, forb uptake, and iron (Fe)-P reactions; and (3) greater P supply through soil and root phosphatase activity and AMF colonization. This work demonstrates that mosses improve vascular plant P acquisition by alleviating stresses caused by reducing conditions that would otherwise prevail in shallow underlying soils, thus providing a mechanism by which mosses facilitate plant species diversity in rich fens. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-1970-8 Authors Katherine F. Crowley, Cary Institute of Ecosystem Studies, Box AB, 2801 Sharon Turnpike, Millbrook, NY 12545, USA Barbara L. Bedford, Department of Natural Resources, Fernow Hall, Cornell University, Ithaca, NY 14850, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Tradeoffs between current reproduction and future survival are widely recognized, but may only occur when food is limited: when foraging conditions are favorable, parents may be able to reproduce without compromising their own survival. We investigated these tradeoffs in the little auk ( Alle alle ), a small seabird with a single-egg clutch. During 2005–2007, we examined the relationship between body mass and survival of birds breeding under contrasting foraging conditions at two Arctic colonies. We used corticosterone levels of breeding adults as a physiological indicator of the foraging conditions they encountered during each reproductive season. We found that when foraging conditions were relatively poor (as reflected in elevated levels of corticosterone), parents ended the reproductive season with low body mass and suffered increased post-breeding mortality. A positive relationship between body mass and post-breeding survival was found in one study year; light birds incurred higher survival costs than heavy birds. The results of this study suggest that reproducing under poor foraging conditions may affect the post-breeding survival of long-lived little auks. They also have important demographic implications because even a small change in adult survival may have a large effect on populations of long-lived species. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1971-7 Authors Ann M. A. Harding, Environmental Science Department, Alaska Pacific University, 4101 University Drive, Anchorage, AK 99508, USA Jorg Welcker, Norwegian Polar Institute, Polarmiljøsenteret, 9296 Tromsø, Norway Harald Steen, Norwegian Polar Institute, Polarmiljøsenteret, 9296 Tromsø, Norway Keith C. Hamer, Institute of Integrative and Comparative Biology, University of Leeds, Miall Building, Leeds, LS2 9JT UK Alexander S. Kitaysky, Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Irving 311, Fairbanks, AK 99775, USA Jérôme Fort, Centre National de la Recherche Scientifique (CEFE), 1919 route de Mende, 34293 Montpellier Cedex 5, France Sandra L. Talbot, Alaska Science Centre, US Geological Survey, 1011 East Tudor Road, Anchorage, AK 99503, USA Leslie A. Cornick, Environmental Science Department, Alaska Pacific University, 4101 University Drive, Anchorage, AK 99508, USA Nina J. Karnovsky, Department of Biology, Pomona College, 175 W. 6th St., Claremont, CA 91771, USA Geir W. Gabrielsen, Norwegian Polar Institute, Polarmiljøsenteret, 9296 Tromsø, Norway David Grémillet, Centre National de la Recherche Scientifique (CEFE), 1919 route de Mende, 34293 Montpellier Cedex 5, France Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within mature individuals. While it is well established that wood density (WD) tends to be lower in early versus late successional tree species, and that WD can influence other aspects of PHA, the interaction of WD, successional stage and the consequent implications for PHA have not been sufficiently explored. Here, we studied differences in PHA at the scales of wood anatomy to whole-tree hydraulic conductance in species in early versus late successional Panamanian tropical forests. Although the trunk WD was indistinguishable between the successional groups, the branch WD was lower in the early successional species. Across all species, WD correlated negatively with vessel diameter and positively with vessel packing density. The ratio of branch:trunk vessel diameter, branch sap flux and whole-tree leaf-specific conductance scaled negatively with branch WD across species. Pioneer species showed greater sap flux in branches than in trunks and a greater leaf-specific hydraulic conductance, suggesting that pioneer species can move greater quantities of water at a given tension gradient. In combination with the greater water storage capacitance associated with lower WD, these results suggest these pioneer species can save on the carbon expenditure needed to build safer xylem and instead allow more carbon to be allocated to rapid growth. Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1973-5 Authors Katherine A. McCulloh, Department of Wood Science and Engineering, Oregon State University, Corvallis, OR 97331, USA Frederick C. Meinzer, PNW Research Station, Forestry Sciences Laboratory, USDA Forest Service, 3200 SW Jefferson Way, Corvallis, OR 97331, USA John S. Sperry, Department of Biology, University of Utah, Salt Lake City, UT 84112, USA Barbara Lachenbruch, Department of Wood Science and Engineering, Oregon State University, Corvallis, OR 97331, USA Steven L. Voelker, Department of Wood Science and Engineering, Oregon State University, Corvallis, OR 97331, USA David R. Woodruff, PNW Research Station, Forestry Sciences Laboratory, USDA Forest Service, 3200 SW Jefferson Way, Corvallis, OR 97331, USA Jean-Christophe Domec, Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC 27695, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Introduced species interact both directly and indirectly with native species. We examine interactions between the introduced New Zealand mud snail ( Potamopyrgus antipodarum) and native estuarine invertebrates and predators through experiments and field studies. A widely held management concern is that when P. antipodarum , which has low nutritional value, becomes abundant, it replaces nutritious prey in fish diets. We tested two key components of this view: (1) that fish consume, but get little direct nutritional value from P. antipodarum ; and (2) that P. antipodarum has an indirect negative effect on fish by reducing the energy derived from native prey. We also examined predation by the native signal crayfish, Pacifastacus leniusculus . Laboratory feeding trials showed that both crayfish and fish consume P. antipodarum , a direct effect. Crayfish consumed and successfully digested higher numbers of snails than did fish [Pacific staghorn sculpin ( Leptocottus armatus ), three spine stickleback ( Gasterosteus aculeatus ), and juvenile starry flounder ( Platicthys stellatus )]. P. antipodarum occurred at low frequencies in the stomachs of wild-caught fish. More interesting were the indirect effects of this invader, which ran counter to predictions. P. antipodarum presence was associated with no change or an increase in the amount of energy derived from native prey by predators. The presence of P. antipodarum also led to increased consumption of and preference for the native amphipod Americorophium salmonis over the native isopod Gnorimosphaeroma insulare . This is an example of short-term, asymmetric, apparent competition, in which the presence of one prey species (snails) increases predation on another prey species (the amphipod). Content Type Journal Article Pages 1-11 DOI 10.1007/s00442-011-1962-8 Authors Valance E. F. Brenneis, Department of Environmental Science and Policy, University of California Davis, One Shields Avenue, Davis, CA 95616, USA Andrew Sih, Department of Environmental Science and Policy, University of California Davis, One Shields Avenue, Davis, CA 95616, USA Catherine E. de Rivera, Department of Environmental Science and Management, Portland State University, P.O. Box 751, Portland, OR 97207, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Birds commonly use rest-phase hypothermia, a controlled reduction of body temperature ( T b ), to conserve energy during times of high metabolic demands. We assessed the flexibility of this heterothermic strategy by increasing roost-site temperature and recording the subsequent T b changes in wintering blue tits ( Cyanistes caeruleus L.), assuming that blue tits would respond to treatment by increasing T b . We found that birds increased T b when roost-site temperature was increased, but only at low ambient temperatures. Moreover, birds with larger fat reserves regulated T b at higher levels than birds carrying less fat. This result implies that a roosting blue tit maintains its T b at the highest affordable level, as determined by the interacting effect of ecophysiological costs associated with rest-phase hypothermia and energy reserves, in order to minimize potential fitness costs associated with a low T b . Content Type Journal Article Pages 1-5 DOI 10.1007/s00442-011-1972-6 Authors Andreas Nord, Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden Johan F. Nilsson, Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden J.-Å. Nilsson, Department of Biology, Section for Evolutionary Ecology, Lund University, Ecology Building, 223 62 Lund, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Biological invasions can vary in the extent of their effects on indigenous communities but predicting impacts for particular systems remains difficult. In coastal marine ecosystems, the green seaweed Codium fragile ssp. fragile is a notorious invader with its reputation based on studies conducted largely on rocky shores. The green seaweed has recently invaded soft-bottom eelgrass communities by attaching epiphytically to eelgrass ( Zostera marina ) rhizomes, thereby creating the potential for disruption of these coastal habitats through competition or disturbance. We investigated the effect of this invader on various aspects of eelgrass performance (shoot density and length, shoot growth, above- and below-ground biomass, carbohydrate storage) using both small-scale manipulative and large-scale observational experiments. Manipulative experiments that varied Codium abundance demonstrated clear negative effects over a 4-month period on shoot density and carbohydrate reserves, but only for high, but realistic, Codium biomass levels. Light levels were much lower under canopies for high and medium density Codium treatments relative to low and control Codium cover treatments, suggesting that shading may influence eelgrass growing under the algal cover. In contrast, these effects were either not detectable or very weak when examined correlatively with field surveys conducted at larger spatial scales, even for sites that had been invaded for over 4 years. It is premature to extend generalizations of Codium ’s impact derived from studies in other systems to eelgrass communities; further efforts are required to assess the long-term threats that the alga poses to this ecosystem. This study demonstrates the need to investigate impacts of invasions over multiple scales, especially those that incorporate the temporal and spatial heterogeneity of the invader’s abundance. Content Type Journal Article Pages 1-12 DOI 10.1007/s00442-011-2086-x Authors Annick Drouin, Ocean and Environmental Sciences Division, Maurice-Lamontagne Institute, Fisheries and Oceans Canada, PO Box 1000, Mont Joli, QC G5H 3Z4, Canada Christopher W. McKindsey, Ocean and Environmental Sciences Division, Maurice-Lamontagne Institute, Fisheries and Oceans Canada, PO Box 1000, Mont Joli, QC G5H 3Z4, Canada Ladd E. Johnson, Département de biologie and Québec-Océan, Université Laval, Québec, QC G1V 0A6, Canada Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description: Erratum to: Abiotic stress mediates top-down and bottom-up control in a Southwestern Atlantic salt marsh Content Type Journal Article Pages 1-1 DOI 10.1007/s00442-011-2101-2 Authors Juan Alberti, Laboratorio de Ecología, Departamento de Biología (FCEyN), Universidad Nacional de Mar del Plata, CC 573 Correo Central, B7600WAG Mar del Plata, Argentina Agustina Méndez Casariego, Laboratorio de Ecología, Departamento de Biología (FCEyN), Universidad Nacional de Mar del Plata, CC 573 Correo Central, B7600WAG Mar del Plata, Argentina Pedro Daleo, Laboratorio de Ecología, Departamento de Biología (FCEyN), Universidad Nacional de Mar del Plata, CC 573 Correo Central, B7600WAG Mar del Plata, Argentina Eugenia Fanjul, Laboratorio de Ecología, Departamento de Biología (FCEyN), Universidad Nacional de Mar del Plata, CC 573 Correo Central, B7600WAG Mar del Plata, Argentina Brian R. Silliman, Department of Biology, University of Florida, Gainesville, FL 32611, USA Mark Bertness, Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA Oscar Iribarne, Laboratorio de Ecología, Departamento de Biología (FCEyN), Universidad Nacional de Mar del Plata, CC 573 Correo Central, B7600WAG Mar del Plata, Argentina Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Dispersal limitation and long-term persistence are known to delay plant species’ responses to habitat fragmentation, but it is still unclear to what extent landscape history may explain the distribution of dispersal traits in present-day plant communities. We used quantitative data on long-distance seed dispersal potential by wind and grazing cattle (epi- and endozoochory), and on persistence (adult plant longevity and seed bank persistence) to quantify the linkages between dispersal and persistence traits in grassland plant communities and current and past landscape configurations. The long-distance dispersal potential of present-day communities was positively associated with the amounts of grassland in the historical (1835, 1938) landscape, and with a long continuity of grazing management—but was not associated with the properties of the current landscape. The study emphasises the role of history as a determinant of the dispersal potential of present-day grassland plant communities. The importance of long-distance dispersal processes has declined in the increasingly fragmented modern landscape, and long-term persistent species are expected to play a more dominant role in grassland communities in the future. However, even within highly fragmented landscapes, long-distance dispersed species may persist locally—delaying the repayment of the extinction debt. Content Type Journal Article Category Community ecology - Methods Paper Pages 1-11 DOI 10.1007/s00442-011-2142-6 Authors Oliver Purschke, Department of Earth and Ecosystem Sciences, Lund University, 223 62 Lund, Sweden Martin T. Sykes, Department of Earth and Ecosystem Sciences, Lund University, 223 62 Lund, Sweden Triin Reitalu, Department of Earth and Ecosystem Sciences, Lund University, 223 62 Lund, Sweden Peter Poschlod, Faculty of Biology, University of Regensburg, 93053 Regensburg, Germany Honor C. Prentice, Department of Biology, Lund University, Ecology Building, 223 62 Lund, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Many bee species are adapted to just a few specific plants in order to collect pollen (oligolecty). To reproduce successfully, it is important for oligolectic bees to find and recognise the specific host flowers. In this study, we investigated the role of floral volatiles used by an oligolectic bee to recognise its host plants. We compared the attractiveness of natural and synthetic scent samples of host flowers to foraging-naïve and -experienced Hoplitis adunca (Megachilidae) bees that are specialised on Echium and Pontechium (Boraginaceae) plants. The investigations showed that naïve H. adunca females are attracted to 1,4-benzoquinone. During their lifetime, bees learn additional floral cues while foraging on host flowers. In contrast to naïve ones, experienced H. adunca females use, in addition to 1,4-benzoquinone, other compounds to recognise their host plants. 1,4-Benzoquinone is an uncommon floral compound only known from the host plants of H. adunca , and is therefore ideally suited to be used as a plant-specific recognition cue. Several arthropods use this compound to deter insect predators. Therefore, 1,4-benzoquinone as an attractant in Echium flowers may have evolved from a primary function as a defensive compound against insect herbivores. Content Type Journal Article Category Plant-Animal interactions - Original Paper Pages 1-10 DOI 10.1007/s00442-011-2136-4 Authors Hannah Burger, Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany Stefan Dötterl, Department of Plant Systematics, University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany Christopher M. Häberlein, Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany Stefan Schulz, Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany Manfred Ayasse, Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    The spatial scale of disturbance is a factor potentially influencing the relationship between disturbance and diversity. There has been discussion on whether disturbances that affect local communities and create a mosaic of patches in different successional stages have the same effect on diversity as regional disturbances that affect the whole landscape. In a microcosm experiment with metacommunities of aquatic protists, we compared the effect of local and regional disturbances on the disturbance–diversity relationship. Local disturbances destroyed entire local communities of the metacommunity and required reimmigration from neighboring communities, while regional disturbances affected the whole metacommunity but left part of each local community intact. Both disturbance types led to a negative relationship between disturbance intensity and Shannon diversity. With strong local disturbance, this decrease in diversity was due to species loss, while strong regional disturbance had no effect on species richness but reduced the evenness of the community. Growth rate appeared to be the most important trait for survival after strong local disturbance and dominance after strong regional disturbance. The pattern of the disturbance–diversity relationship was similar for both local and regional diversity. Although local disturbances at least temporally increased beta diversity by creating a mosaic of differently disturbed patches, this high dissimilarity did not result in regional diversity being increased relative to local diversity. The disturbance–diversity relationship was negative for both scales of diversity. The flat competitive hierarchy and absence of a trade-off between competition and colonization ability are a likely explanation for this pattern. Content Type Journal Article Category Community ecology - Methods Paper Pages 1-11 DOI 10.1007/s00442-011-2140-8 Authors Romana Limberger, Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria Stephen A. Wickham, Department of Organismic Biology, University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    This study examined the independent and interactive effects of elevated carbon dioxide (CO 2 ) and ozone (O 3 ) on the foliar quality of two deciduous trees species and the performance of two outbreak herbivore species. Trembling aspen ( Populus tremuloides ) and paper birch ( Betula papyrifera ) were grown at the Aspen FACE research site in northern Wisconsin, USA, under four combinations of ambient and elevated CO 2 and O 3 . We measured the effects of elevated CO 2 and O 3 on aspen and birch phytochemistry and on gypsy moth ( Lymantria dispar ) and forest tent caterpillar ( Malacosoma disstria ) performance. Elevated CO 2 nominally affected foliar quality for both tree species. Elevated O 3 negatively affected aspen foliar quality, but only marginally influenced birch foliar quality. Elevated CO 2 slightly improved herbivore performance, while elevated O 3 decreased herbivore performance, and both responses were stronger on aspen than birch. Interestingly, elevated CO 2 largely offset decreased herbivore performance under elevated O 3 . Nitrogen, lignin, and C:N were identified as having strong influences on herbivore performance when larvae were fed aspen, but no significant relationships were observed for insects fed birch. Our results support the notion that herbivore performance can be affected by atmospheric change through altered foliar quality, but how herbivores will respond will depend on interactions among CO 2 , O 3 , and tree species. An emergent finding from this study is that tree age and longevity of exposure to pollutants may influence the effects of elevated CO 2 and O 3 on plant–herbivore interactions, highlighting the need to continue long-term atmospheric change research. Content Type Journal Article Category Global change ecology - Original Paper Pages 1-14 DOI 10.1007/s00442-011-2139-1 Authors John J. Couture, Department of Entomology, University of Wisconsin, Russell Laboratories, 1630 Linden Dr., Madison, WI 53706, USA Timothy D. Meehan, Department of Entomology, University of Wisconsin, Russell Laboratories, 1630 Linden Dr., Madison, WI 53706, USA Richard L. Lindroth, Department of Entomology, University of Wisconsin, Russell Laboratories, 1630 Linden Dr., Madison, WI 53706, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Cross-ecosystem movements of material and energy are ubiquitous. Aquatic ecosystems typically receive material that also includes organic matter from the surrounding catchment. Terrestrial-derived (allochthonous) organic matter can enter aquatic ecosystems in dissolved or particulate form. Several studies have highlighted the importance of dissolved organic carbon to aquatic consumers, but less is known about allochthonous particulate organic carbon (POC). Similarly, most studies showing the effects of allochthonous organic carbon (OC) on aquatic consumers have investigated pelagic habitats; the effects of allochthonous OC on benthic communities are less well studied. Allochthonous inputs might further decrease primary production through light reduction, thereby potentially affecting autotrophic resource availability to consumers. Here, an enclosure experiment was carried out to test the importance of POC input and light availability on the resource use in a benthic food web of a clear-water lake. Corn starch (a C 4 plant) was used as a POC source due to its insoluble nature and its distinct carbon stable isotope value (δ 13 C). The starch carbon was closely dispersed over the bottom of the enclosures to study the fate of a POC source exclusively available to sediment biota. The addition of starch carbon resulted in a clear shift in the isotopic signature of surface-dwelling herbivorous and predatory invertebrates. Although the starch carbon was added solely to the sediment surface, the carbon originating from the starch reached zooplankton. We suggest that allochthonous POC can subsidize benthic food webs directly and can be further transferred to pelagic systems, thereby highlighting the importance of benthic pathways for pelagic habitats. Content Type Journal Article Category Ecosystem ecology - Original Paper Pages 1-12 DOI 10.1007/s00442-011-2141-7 Authors Pia Bartels, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Julien Cucherousset, Centre for Conservation Ecology and Environmental Sciences, School of Applied Sciences, Bournemouth University, Poole, Dorset, UK Cristian Gudasz, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Mats Jansson, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden Jan Karlsson, Department of Ecology and Environmental Science, Climate Impacts Research Centre, Umeå University, Abisko, Sweden Lennart Persson, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden Katrin Premke, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Anja Rubach, Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden Kristin Steger, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Lars J. Tranvik, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Peter Eklöv, Department of Ecology and Genetics/Limnology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Nutritional and thermal regimes experienced early in life can strongly influence offspring quality and ultimately adult life histories, especially in ectotherms. However, the importance of the interaction between diet and temperature during postnatal development and the effect on offspring quality are unknown. We compared offspring quality (size, shape, speed, behavior, and survival) of juvenile McCann’s skinks ( Oligosoma maccanni ) housed outdoors under variable thermal conditions (under shelter, but exposed to daily and seasonal variations in light and temperature) with those housed indoors under more stable thermal conditions (controlled temperatures providing 30–40% more basking opportunity) and with a control group (open field conditions). For those caged in captivity (indoors and outdoors), we also compared outcomes between those fed a restricted diet and those fed ad libitum. By comparing individuals raised under different environmental regimes, we aimed to determine whether direct effects of temperature or indirect effects of food supply are more important for offspring quality. Individuals provided with food ad libitum grew faster, and attained larger sizes than those raised on a restricted diet or in the field. Activity rates were higher in individuals exposed to stable rather than variable thermal conditions. Survival post release in the field was highest for larger neonates, and lowest in individuals raised under stable thermal conditions and a restricted diet. We found little evidence for effects of an interaction between feeding and thermal regimes on most factors measured. However, the conditions experienced by young animals (especially diet) do influence important traits for population persistence, such as survival, and may influence key reproductive parameters (e.g., age and size at maturity), which could have implications for conservation management. Further research, including the ultimate influence of early environmental conditions on fecundity and life expectancy, is urgently needed. Content Type Journal Article Category Physiological ecology - Original Paper Pages 1-11 DOI 10.1007/s00442-011-2145-3 Authors Kelly M. Hare, Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054 New Zealand Amanda J. Caldwell, Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054 New Zealand Alison Cree, Department of Zoology, University of Otago, PO Box 56, Dunedin, 9054 New Zealand Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549

Description:    Elevated temperatures and diminished precipitation amounts accompanying climate warming in arid ecosystems are expected to have adverse effects on the photosynthesis of lichen species sensitive to elevated temperature and/or water limitation. This premise was tested by artificially elevating temperatures (increase 2.1–3.8°C) and reducing the amounts of fog and dew precipitation (decrease 30.1–31.9%), in an approximation of future climate warming scenarios, using transparent hexagonal open-top warming chambers placed around natural populations of four lichen species ( Xanthoparmelia austroafricana , X. hyporhytida , Xanthoparmelia . sp., Xanthomaculina hottentotta ) at a dry inland site and two lichen species ( Teloschistes capensis and Ramalina sp.) at a humid coastal site in the arid South African Succulent Karoo Biome. Effective photosynthetic quantum yields ( \Updelta F / F \text m ¢ ) were measured hourly throughout the day at monthly intervals in pre-hydrated lichens present in the open-top warming chambers and in controls which comprised demarcated plots of equivalent open-top warming chamber dimensions constructed from 5-cm-diameter mesh steel fencing. The cumulative effects of the elevated temperatures and diminished precipitation amounts in the open-top warming chambers resulted in significant decreases in lichen \Updelta F / F \text m ¢ . The decreases were more pronounced in lichens from the dry inland site (decline 34.1–46.1%) than in those from the humid coastal site (decline 11.3–13.7%), most frequent and prominent in lichens at both sites during the dry summer season, and generally of greatest magnitude at or after the solar noon in all seasons. Based on these results, we conclude that climate warming interacting with reduced precipitation will negatively affect carbon balances in endemic lichens by increasing desiccation damage and reducing photosynthetic activity time, leading to increased incidences of mortality. Content Type Journal Article Category Global change ecology - Original research paper Pages 1-12 DOI 10.1007/s00442-011-2184-9 Authors Khumbudzo Walter Maphangwa, Climate Change and Bio-Adaptation Division, South African National Biodiversity Institute, Private Bag X7, Claremont, 7735 Cape Town, South Africa Charles F. Musil, Climate Change and Bio-Adaptation Division, South African National Biodiversity Institute, Private Bag X7, Claremont, 7735 Cape Town, South Africa Lincoln Raitt, Department of Biodiversity and Conservation Biology, University of Western Cape, Private Bag X7, Bellville, 7535 South Africa Luciana Zedda, Abt Mykologie NW1, Lehrstuhl für Pflanzensystematik, Universitätsstrasse 30, 95440 Bayreuth, Germany Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549